Hesitation, Sputtering When Giving Car Gas

[thetailgatespecialist]

I'm really in a bind. Bought a used '93 LS400 for my kid that was a trade in at a local used car dealer. The car wouldn't stay started and the owner of the car lot told me it was the mass air flow sensor. Had that changed and car was running fine. As I drove off the lot at a high rate of speed, car was fine for 2 miles. All of sudden when trying to press down on the accelerator to give it gas....here comes the sputtering and missing. When I put it in park, it revs up fine. Once i put it into drive, the sputtering and missing comes into play. I NEED HELP...someone please lead me in the right direction. Money is funny right now.

The Tailgate Specialist

[charlesranderson]

I'm really in a bind. Bought a used '93 LS400 for my kid that was a trade in at a local used car dealer. The car wouldn't stay started and the owner of the car lot told me it was the mass air flow sensor. Had that changed and car was running fine. As I drove off the lot at a high rate of speed, car was fine for 2 miles. All of sudden when trying to press down on the accelerator to give it gas....here comes the sputtering and missing. When I put it in park, it revs up fine. Once i put it into drive, the sputtering and missing comes into play. I NEED HELP...someone please lead me in the right direction. Money is funny right now.

The Tailgate Specialist

[charlesranderson]

Had a similar problem with a '91 LS400. Not really sputtering, but there would suddenly be no power when accelerator depressed--although engine would stay on for a while. Car would start fine and accelerate to almost any speed, but as soon as the accelerator was backed off, there was no more power going to the wheels and the engine would not even rev up. Was intermittent, but often occurred when hot after extensive stop and go driving.

Then, would occur after only a little regular driving. Sometimes problem would clear up for a while after car sat and cooled.

Replaced the fuel pump and and had no further problems.

[Acidic]

It could be a number of things... and it could be any of the systems or just a sensor... if you don't know how to troubleshoot and money is tight take it to a mechanic for troubleshooting then do the work yourself...

You can also check the basics yourself... inspect plugs/wires/rotors for anything obvious, check for vac leaks, rips in intake etc.... the fuel pump is plausible as well but I don't know how to test one... If you don't get a good diagnosis you could be throwing parts at it for awhile

[davispb]

Had a similar problem with a '91 LS400. Not really sputtering, but there would suddenly be no power when accelerator depressed--although engine would stay on for a while. Car would start fine and accelerate to almost any speed, but as soon as the accelerator was backed off, there was no more power going to the wheels and the engine would not even rev up. Was intermittent, but often occurred when hot after extensive stop and go driving.

Then, would occur after only a little regular driving. Sometimes problem would clear up for a while after car sat and cooled.

Replaced the fuel pump and and had no further problems.

Had this on my '92. Not the exact same symptoms, but I would start with FUEL PUMP, if I were you, tailg8 guy.

[thetailgatespecialist]

I have changed the fuel pump as well as a few sensors in my 1993 Lexus LS400. The car is still sputtering...hesitating to pick up speed at the rate it should. What else could it be? Even tried some injection cleaners

[curiousB]

First thing I would do is check ECU codes to see if any clues there.

Failing that then its either ignition or fuel. You can test fuel buy purchasing a fuel pressure gauge for around $15-20. That will tell you if the pressure is correct and if it holds pressure while driving. Even with a new fuel pump if could be a fuel problem such as clogged fuel filter. Generally though that will result in performance drop off at higher speeds than simple starts from stop.

My bet is ignition related. Are you getting any backfiring or are the catalytic converters red hot. This could be a sign of unspent fuel getting to exhaust system. Common failures on these cars is to lose one ignition coil and effectively turn the car into a 4 cylinder and you'll see rough performance. Ignition coil, low volatage wiring to coil, plug wires, or crankshaft position sensor are possibilities.

You can search this forum for ignition or coil and you'll find helpful tips on how to diagnose further.

[CarLuvrSD]

I have changed the fuel pump as well as a few sensors in my 1993 Lexus LS400. The car is still sputtering...hesitating to pick up speed at the rate it should. What else could it be? Even tried some injection cleaners

I've had similar issues over the years on my 92 ES. It's always been an intake air leak or failing/craked distributor cap.

[CrownRoyal82]

Hi. Were you able to fix your problem with your Ls? Iam having similar problems now.Thanks

[VBdenny]

I would suggest you follow the advice curious offered. Don't screw around, drive that unit over to Advance or Auto Zone and use their OBDII scanner to find out what is wrong. Not sure if you mentioned the Check Engine light but it seems that if the car is running that badly, there must be a code stored. Both places let you use the OBDII for free. I use it to turn off the CE light on my truck before I get it inspected. Regarding the sputtering, the cheapest solution I can suggest is to dump in 2 bottles of Valvoline Complete Fuel System Cleaner. They cost $10 each so for $20, you might fix it. I had a friend that had a Cadillac doing the same thing. The dealer replaced the computer which didn't fix it but the Valvoline cleaner did. Check the codes.