A Few Questions

[CanadaCraig]

Hi Guys!! :)

SEMI-UPDATE:

All the dealer did [after driving it extensively] was flush all the fuel injectors - twice. It does seem to have more power once it's on the move. In fact - lately - it has been better - more often than it used to be. [which is good] And when it's good - it's great!! But it still has that 'I am pulling a trailer' feeling to it. And now the brakes [front - I think] need to be 'turned' again. [or whatever] They vibrate REALLY badly if applied at speeds above 80 mph.

Here are a few questions.

1. Dealer suggested that I unplug the EGR valve to see if there is any improvement. So I did. No difference at all. Which surprises me. Shouldn't something have happened? [either good or bad] The CEL hasn't even come on and the EGR thing has been unplugged for couple of days now. I'm confused.

2. Tires. Can tires [all four in my case] 'cup' even if the suspension, alignment, balancing and tire air pressure are OK? [and have been all along?] My Bridgestone Turanza LS-V's have over 40,000 km's on them. Dealer strongly suggests replacing them with Michelin Pilot Sport A/S. I think that's what I'm going to do. But I'm concerned. I don't want them to 'cup' too.

3. Dealer did the 'bounce test' to check the condition of the struts. It 'passed'. But wouldn't new OEM struts improve the ride all the same? [particularly how stable the car feels on the freeway] AND maybe level off the car. [being that it's lower on the driver's side by about 3/4's of an inch or so]

4. And speaking of brakes - COULD a slightly dragging brake [or parking brake?] cause a 'surging feeling'? [and that 'I am pulling a trailer' feeling?]

5. Could any of the above cause my car to only get [on average] 17.3 miles per U.S. gallon?!

Thanks

Craig!! :)

[andre]

have you checked rear brakes?

i also suspected front rotors, but after i took care of them my rears breaks were inspected -they were never checked? rotors were worned out and pads were gone too...

try that -you will be surprised how well it will break

[nc211]

Hi Guys!! :)

SEMI-UPDATE:

All the dealer did [after driving it extensively] was flush all the fuel injectors - twice. It does seem to have more power once it's on the move. In fact - lately - it has been better - more often than it used to be. [which is good] And when it's good - it's great!! But it still has that 'I am pulling a trailer' feeling to it. And now the brakes [front - I think] need to be 'turned' again. [or whatever] They vibrate REALLY badly if applied at speeds above 80 mph.

Here are a few questions.

1. Dealer suggested that I unplug the EGR valve to see if there is any improvement. So I did. No difference at all. Which surprises me. Shouldn't something have happened? [either good or bad] The CEL hasn't even come on and the EGR thing has been unplugged for couple of days now. I'm confused.

2. Tires. Can tires [all four in my case] 'cup' even if the suspension, alignment, balancing and tire air pressure are OK? [and have been all along?] My Bridgestone Turanza LS-V's have over 40,000 km's on them. Dealer strongly suggests replacing them with Michelin Pilot Sport A/S. I think that's what I'm going to do. But I'm concerned. I don't want them to 'cup' too.

3. Dealer did the 'bounce test' to check the condition of the struts. It 'passed'. But wouldn't new OEM struts improve the ride all the same? [particularly how stable the car feels on the freeway] AND maybe level off the car. [being that it's lower on the driver's side by about 3/4's of an inch or so]

4. And speaking of brakes - COULD a slightly dragging brake [or parking brake?] cause a 'surging feeling'? [and that 'I am pulling a trailer' feeling?]

5. Could any of the above cause my car to only get [on average] 17.3 miles per U.S. gallon?!

Thanks

Craig!! :)

Craig, here is my story with these items, except for the EGR:

1) I don't know, haven't had a problem with the EGR...yet..

2) I think it also depends on how old the tires are, and how long the car sits in one place. I know for a fact "dad has 12 cars" that older tires that sit for a long time will flat-spot, which can lead to cupping. We have an old Caddy "73" that sits for months at a time "only has 13k original miles". The tires flat spot, then after driving, will cup. Also have a 85 MB 500 SEL w/ 38k miles, that does the same thing. But, you seem to drive your car more often. Do I think they could cup? Yes. It is quite possible they just have worn out to the point where they cup. I have the Michelin mvx4's on mine now, and love them. I have had zero problems with them. The car sat at the airport for 3 weeks back in May, and there was no sign of flat-spotting when we got back. Just a ton of bird crap, looked like a pack of Terridacticles used it for bomb runs.

3) Yes... New struts will improve the over all control, stability and level ride. Take caution though, as you already know from others on here, you can over-stiff the ride with aftermarket struts, but just depends on your taste. I know Blake recently installed new oem struts on his 95', and he said it lifted the rear of the car about 3/4 inch. If you're leaning, I bet you're ready for some new struts. I've noticed the "bounce test" is useless, in my opinion. It doesn't take into consideration the fact that the car is MOVING when it's bouncing.

4) Yes, it can create that feel. It would also make the rear of the car feel like it's lowering when you drive. Just like if you apply the e-brake, put the car in drive and let it surge forward. You'll notice the rear end drops a little. Easiest thing to do is remove the rotors, clean out the inside, the e-pads and turn the little metal spindle a few clicks to adjust the e-brake setting. But, take caution again, don't turn the spindle too much, as you'll completely eliminate the ebrake option. It takes a few test runs to make sure it will still work.

But, yes, you are correct, a dragging ebrake can give you that feeling, especially if only one side is dragging.

5) I would think the ebrake theory would be the most likely canidate to the reduced gas mileage. The worn struts would contribute a little, but mostly in control ability on the highway. It sounds like to me you have a problem of operation, which is creating mechanical drag.

Question: Have you had the driveshaft looked at? I recently learned that the LS400 can suffer from a binding center bearing in the driveshaft. Mine was recently replaced, and it made a world of difference in the operational smoothness of the car. I had a surging feeling too, especially early in the morning when I would pull out of the neighborhood and head up the hill. But I also had a very fast vibration under my seat that tipped me off to the problem. It is unusual for the driveshaft to be bad if it doesn't give off some sort of vibration...

I'd check your rear ebrake first, sounds like a likely cause. It's obvioulsy taking a hell of a lot more gas to turn those wheels back there.

PS: My rotors are warped too. I have new Mountains on the front, and cheapo' Napa's on the back. All are warped. I'm going to do the caliper rebuild kit soon, have the front rotors turned, rear rotors replaced with OEM, and flush the system. Just waiting for it to cool down below "hell+20 degrees".

[93ls400walt]

A repair manual ststes that cupping maybe caused by:

1) Underinflation

2) out of balance

3) bent wheel

4)loose or worn tie-rods or steering idler arm

5) loose,worn or damaged front suspension parts

I always thought that it could be caused by worn shocks/struts letting the tire " bounce " as you drive.

[1990LS400]

Craig, give it up! I'd say you are doing great to be getting 17.3 miles per U.S. gallon while living in Victoria and driving on Vancouver Island. We've ferried a car from Anacortes to Vancouver Island several times -- my cousin has a hobby farm on San Juan Island and we have lots of relatives in the Seattle area. We have spent weeks at a time on Vancouver Island and have driven from the southern tip to about as far north as one can drive -- where the "gravel" on the mountain logging roads are as big as boulders and we take commercial cargo/passenger boats to go further north. My guess is that virtually all your driving is what I would call "city driving" here in the midwest U.S. -- except I'd bet that we do a lot less stop and go driving in Kansas City than you do around Victoria. 17.3 miles per U.S. gallon in an early 4-speed automatic LS400 in Victoria sounds wonderful to me.

And where the heck are you doing 80 mph on Vancouver?

[CanadaCraig]

Hi nc211!! :)

I hope you're OK.

Thank you VERY much for the response. It would have taken you quite some time to write all that - and I appreciate it.

Regarding the driveshaft - YES it was looked at. But more than that - it was taken OFF [about two years ago] and balanced in an attempt to solve a 'droning' sound that occurred at around 50 MPH. The sound is still there - but it's not nearly as offensive. Part of me has always suspected that something might be wrong with the driveshaft. And to be honest - I wasn't all that comfortable with the idea that they took it off. Then again - the car DOES perform beautifully - sometimes - which makes me question the driveshaft binding idea. [or it being out of alignment or whatever] Still.... something to consider. [As is the e-brake dragging theory]

Thanks again,

Craig!! :)

Hi andre!! :)

I hope you're OK.

Thanks for the advice. I'll make sure they check ALL the brakes. [front, back AND 'emergency'] I'm often frustrated by how some mechanics will only consider what's being asked of them. If someone is complaining about the brakes not feeling right and THEY THINK it's the front brakes - a mechanic should thoroughly inspect ALL the brakes - just in case.

Craig!! :)

A repair manual ststes that cupping maybe caused by:

1) Underinflation

2) out of balance

3) bent wheel

4)loose or worn tie-rods or steering idler arm

5) loose,worn or damaged front suspension parts

I always thought that it could be caused by worn shocks/struts letting the tire " bounce " as you drive.

Hi 93ls400walt!! :)

I hope you're OK.

Thanks for the INFO.

You still might be right. I've read quite a few website articles that DID say worn shocks/struts can cause cupping. And really - doesn't that make sense? [along with all of the other possibilities?!] I think so.

Craig!! :)

[CanadaCraig]

Hi 1991LS400!! :)

I hope you're OK - too!!

I suppose I was surprised to discover that my 425 h.p. Chrysler gets 1 more MPG on average than my 250 h.p. Lexus. As for 'where can one drive 80 mph on Vancouver Island' - well - there are quite a few places. Just from Victoria to Sidney [where the big ferries dock] is a good place. And from Victoria to Sooke. [which is west of Victoria] Also the Malahat [the drive over and through the mountains on the way to Nanaimo] is good too. But yes - like any other city - most driving within the city IS 'stop and go'. I appreciate what you're saying though. But ME 'give it up'?! Not likely. I'm far to obsessive to do anything THAT rational!! lol :P

Craig!! :)