91 Ls 400 Went Nuts On Me... Now It's Sane?

[914lps]

I was 200 miles into a long drive. Car temp was good. Under the half way mark. With about 1/2 talk of gas left. Car had been running great with cruise controll set at 85. I stopped at a rest stop for about 5 Min. When i took to the road car ran like sh*&^. Nothing at low speed. Just like it was running out of gas. If I put car in N the engine reved fine. Put back in drive. Would act like not getting gas. Finailly hit 50 mph and car ran great got back up to 85. Then hit a slow zone and had to go to 40 mph. again car ran like was not geting gas till

I hit 50 or more. I tried turning OD on and off... no help. Going down hill. I put the car in N and turned it off, and restarted the car. Put back in drive. Car has been o.k. for two days now. What happened?????????????? I checked under the hood. No loose conections, all vacum lines o.k.... all conectors o.k. oil ok. trany fliud o.k.?????? What happened?????? The only thing I can think of is the "computer" was messed up, and restarting it reset it????

[RFeldes]

Fuel filter more than likely, cheapest fix. Check that first and then follow the advice I'm sure will follow if that doesn't do it. Same thing happened with my 85 Corvette. On the highway it started choking and running rough and I would pull over for ten minutes then it ran fine for maybe 50 miles or it would go away for a week in town. Back on the highway, same problem. They changed one thing then it ran fine and then the problem came back then they changed another thing and problem came back. When it was finally fixed the mechanic explained that the filter would clog and then when the car was calling for less fuel the pressure would back off and the car would run fine. Once I got back on the highway and started running a lot of fuel the clog would come back to the filter and once again the chocking of the engine. Cost me $600 to find out a $5 fuel filter was the problem. When they pulled the filter a large. expensive fuel clog, putting it mildly, came out from the draining fuel. Maybe it's not your problem but it sure was mine.

What a ghost in the closet that was. It cost me a lot of quality time with a beautiful babe and I will never forget it. Ranting......Sorry!

[spiller91ls]

there is another set of trottle blades in your intake, it's more like a choke. if you look where your trottle cable hooks up you will see another TPS a few inches to the driver side of it. If you check your engine codes (hook up te1 and e1 on top of manifold) you should get a code 41, loss of TPS signal. If you did notice when it did happen, your check engine light was on, correct??? Just pull over and let the light go off the next time it happens, then continue on your way.

my 91 will do the same thing on cold mornings, and i'm about to remove or disable the darn thing.

[RFeldes]

Spiller 91ls has a good point if your "check engine" light came on.

[914lps]

To 1st responce. I do not think it is the filter. The car would rev fine when out of gear. Only acting like out of gas when in gear at low speed. Car ran fine at high end (over 50 mph). Also started after car was stoped.

On second responce. I had no check eng. or other lights on.

Good thing is car is still running fine.......

I have to make another long haul this coming week. We will see.

[914lps]

Car still running fine... in 24 hours I hit the road for a 600 mile drive. We will see????

[tonupkid]

I have another idea for you.

How about your auto box is switching into 'get you home mode'. I think this will leave your car in a high gear, whatever speed your going. So, at low speeds you have no power at all, but as your speed picks up to match the 'get you hame' gear setting, eveything appears ok again.

Think of it like driving aroung in a manual (stick shift, I think you would call it) stuck in 5th gear. Pretty lousy at pulling off, but once you got up to about 50, everything would seem normal.

Switching the car off would give your car the chance to reset (as you said).

I once had this exact problem on a GM. Mechanic reckoned it was a stray signal from a spark plug, that corrupted the data in the auto box controller, causing the controller to flip into emergency mode. Changed the plugs and it was fine from then on.

This is just a guess, I know sod all about them, but it seems to fit your description.

Good luck with it

[VBdenny]

When that happens, take your gas cap off for a minute and let the pressure equalize. You had a little vapor lock it sounds like. Shouldn't happen but often after high speed driving it is a good idea to let your car idle for a minute or so before shutting it off to get systems squared up.

[914lps]

When that happens, take your gas cap off for a minute and let the pressure equalize.  You had a little vapor lock it sounds like.  Shouldn't happen but often after high speed driving it is a good idea to let your car idle for a minute or so before shutting it off to get systems squared up.

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If it was vapor lock, then why would restarting the car (without stopping) fix it????

[tonupkid]

As I understand it your LS will hiss when you remove the4 gas cap, because thats the way the car is designed. The fuel tank is intentionally preasurised so as to reduce vapour emmissions into the enviroment.

Check what gear your car is in when it goes gutless on you (not by reading the dash) but perhaps by manually downshifting the box or jus observing the upshifts that should be there as your speed increasers (pretty hard on a Lex)

[914lps]

As I understand it your LS will hiss when you remove the4 gas cap, because thats the way the car is designed. The fuel tank is intentionally preasurised so as to reduce vapour emmissions into the enviroment.

Check what gear your car is in when it goes gutless on you (not by reading the dash) but perhaps by manually downshifting the box or jus observing the upshifts that should be there as your speed increasers (pretty hard on a Lex)

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Car is still o.k. and has not done it again. When it did happen I I flipped O/D on and off severail times, back and forth. Same with the economy swicth. It was no help. I also treid putting the car into "2" from drive. No help. But it all when away by doing a complet restart.

I'm wondering if this has happened to anyone else. I know a bad coil can give the actionn I was getting, but a restart would not have helped. It could also have been a bad fuel pump, but again, a restart would not have helped.

I did the restart going doen hill at about 60 mph. Put the car in "N" turned it off (being carefull not to lock the streeing wheel, checked the tach to see that egine was not turning, turned key back on and bumped the starter to get engine going. Put back into drive, and all has been o.k. ...so fare

[tonupkid]

When you put it into 2nd did you feel it change down? If it did not, there is your problem.

Is it possible to get a log og faults out from the car? I don't know, but perhaps someone can help.

[914lps]

When you put it into 2nd did you feel it change down? If it did not, there is your problem.

Is it possible to get a log og faults out from the car? I don't know, but perhaps someone can help.

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91 ls did not hold codes as I understand it.... and as I was only goingabout 20 mph and car was jerking etc., I would not haave felt it *BLEEP*ing or not

[914lps]

O.K. just an update. Have put abou 1,500 miles on the car. Including doing the above drive over again. Car has never acted up again. Hope it never will!!! But now the power steering pump is going out :cries:

[VBdenny]

I still think it was just a case of getting a little extra fuel into the cylinders as you shut down. Once the spark plugs get so wet it takes them awhile to burn clean again. Whenever I drive at high speeds for awhile I always let the car idle for a minute or two before I shut it off. Probably just a load of crappy gas.

[cardona6569]

I still think it was just a case of getting a little extra fuel into the cylinders as you shut down.  Once the spark plugs get so wet it takes them awhile to burn clean again.  Whenever I drive at high speeds for awhile I always let the car idle for a minute or two before I shut it off.  Probably just a load of crappy gas.

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Hello: I think is in order for you to change your fuel filter, and put some Lucas Injector cleaner into your tank. It must have some sludge in there by this time. The fuel filter has lasted a very longtime so it is time for a new one, even as it is not doing it again but it will come back if you do not clean de system and change the filter, because then it could clog the pump. Use Texaco system 3 it will keep it cleaner also. C

[914lps]

I thank you for the thoughts, but I do not think it was bad gas, as after I turned the car off, then back on, everything was fine. If it was gas, or a cloged line etc., turning on and off would have done nothing. Also do not think it was plugs. As car would rev fine in "P" or "N", but would not run right in gear, till I got over 50 mph, and would act up againn if I went under 50 mph, this went on for over 20 miles till I turned car off and restarted it. Plugs either do or do not fire... But speed and load would not effect the plugs fireing. I think it was somethink that gliched in either the electronics of the grear box, or engine control. But it has not come back.

Thank God....... I'll take a good running carer anyway I can get it, and if I have to thank God for my car running right... It's a lot cheaper then paying the shop...... :o

[cardona6569]

I thank you for the thoughts, but I do not think it was bad gas, as after I turned the car off, then back on, everything was fine.  If it was gas, or a cloged line etc., turning on and off would have done nothing.  Also do not think it was plugs.  As car would rev fine in "P" or "N", but would not run right in gear, till I got over 50 mph, and would act up againn if I went under 50 mph, this went on for over 20 miles till I turned car off and restarted it.  Plugs either do or do not fire... But speed and load would not effect the plugs fireing.  I think it was somethink that gliched in either the electronics of the grear box, or engine control.  But it has not come back. 

Thank God....... I'll take a good running carer anyway I can get it, and if I have to thank God for my car running right... It's a lot cheaper then paying the shop...... :o

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Hi: I also would advise to clean the Throttle Body and the Mass airflow sensor, I had a GM car do something like that and it was the sensor it will stall and when turned off will quit doing it, then we took it to the dealer because it was almost new and they replaced the said sensor, never had that problem again and it ran about 245,000 miles. I do not tell you to replace the air filter because I imagine you do it at the recommend mileage, you can also buy a K&N filter that lasts a lifetime, if properly cleaned every 50,000 miles. You can find both tutorials at the www.lexls.com page, they will not cost you more than five bucks, but be carefull cleaning the mass airflow sensor, the one that is after the air filter element that looks like a cigarrette box, the tutorial shows step by step I did it with no problems. But I still insist that you at this time should at least put some cleaning additive to the gasoline Lucas, Techtron are both great! even Snap is good also. Yes, it is not the spark plugs, but those you need to change as mandated and will never have problems with them. Let us know if the problem comes back and clean the sensor.

C. PR

[914lps]

The car had a major tune up about 3 or 4 months ago. TB was sparkling clean. I use an additive in the gas every 3 to 5,000 miles. I like the stuff made by "chemtool".

[cardona6569]

The car had a major tune up about 3 or 4 months ago.  TB was sparkling clean.  I use an additive in the gas every 3 to 5,000 miles.  I like the stuff made by "chemtool".

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Hello: If did the tune up, Clean the Mass/Airflow sensor, I think there lies your problem. C.

[914lps]

If it was mass air flow why would car rev ok, buy have trouble under load??? Also way would truning off and on make everything ok. As I have put upwards of 2,000 miles on the car with no repete of event I still think it was strange one time computer thing????

[cardona6569]

If it was mass air flow why would car rev ok, buy have trouble under load???  Also way would truning off and on make everything ok.  As I have put upwards of 2,000 miles on the car with no repete of event I still think it was strange one time computer thing????

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Hello: My past experienced with the mass/airflow was like yours, when turned off the car ran ok sometimes for a whole day then the problem comes back. Second, you may not need to replace the airflow/airfilter, you need to clean both of them, because if they are not clean the performance info to the computer gets wrong and freaky things happens. But believe the problem if left without looking into will come back. I am just suggesting you clean the mass/airflow, what wrong could you do with that, you already have change the air filter as part of the major tune up. When you put more load to the car, your air/flow quantity increases, if that sensor is dirty/faulty I think in your case is just dirty, you will have problems. But you could leave things as they are, soon enough your car will give the message in a loud no confussion way.

Hey how did you come out with the P/S pump problem? Cost?

C.

PD. Have you check the tutorials? The person who does them has an email an replies to you if you have question.

[914lps]

Air filter is clean. After every long drive (600+) miles I blow it clean. It picks up lots of bugs going though the desert.

How do you clean Mass Air Flow unit? I pulled mine and it looks clean (wire grid).

On Power steering. Auto zone has a rebuilt unit without the resuvor, with lifetime warntee for under 140.00 . After you return you old core unnit cost is about 120.00.

I have one on order. You have to go in to order it. It dose not show on the internet.

I'm just going to replace the unit, clean screens, and flush and fill. On Friday the thing started to sound like it was going to explode. Other dirvers were lookinh at me, the thing was so loud. And I lost low end power.

But yesterday, it got better, you could hardly hear it, and had power at all speeds. As I know the screens are clean or close to it, I'm sure the pump is the bad guy.

So for about 200.00 to 225.00 with the paid labor, I'll just play it safe and replace it. The pump on the car was rebuilt by dealer at 60,000 miles. Now has 130,000 miles on it. Not bad for a 91. I got it about 3 years ago with about 90,000 on it.

[cardona6569]

Air filter is clean.  After every long drive (600+) miles I blow it clean.  It picks up lots of bugs going though the desert.

How do you clean Mass Air Flow unit?  I pulled mine and it looks clean (wire grid).

On Power steering.  Auto zone has a rebuilt unit without the resuvor, with lifetime warntee for under 140.00 .  After you return you old core unnit cost is about 120.00.

I have one on order.  You have to go in to order it.  It dose not show on the internet.

I'm just going to replace the unit, clean screens, and flush and fill.  On Friday the thing started to sound like it was going to explode.  Other dirvers were lookinh at me, the thing was so loud.  And I lost low end power.

But yesterday, it got better, you could hardly hear it, and had power at all speeds.  As I know the screens are clean or close to it, I'm sure the pump is the bad guy.

So for about 200.00 to 225.00 with the paid labor, I'll just play it safe and replace it.  The pump on the car was rebuilt by dealer at 60,000 miles.  Now has 130,000 miles on it.  Not bad for a 91.  I got it about 3 years ago with about 90,000 on it.

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Hi here is the link to clean your sensor, with photos.

http://us.lexusownersclub.com/forums/index...view=getnewpost

C. PR

[914lps]

The link you put up does not go to the info on the mass air.... It goes right back to this post.... Opps....