Big Daddy

Hello all, I am hoping I can get a little help on here for my '94 LS400. Here is my story:


The Problem
When starting the car the RPMs will run 1600 at idle; this is the same even after it has warmed up.

It is impossible to rev it over 2800 RPMs in Park or Neutral. It studders and then drops down to 1300 ~ 1600 RPMs and bounces back and forth until you release the accelerator.

In drive it goes to 1200 RPMs with the break applied.

To take off it has no power at all, UNLESS you manually shift it down to D1, at which point it is raring to go.

When you are driving it will not go over 2100 RPM without the aformentioned studdering. The car will drive beautifully between 40 and 60, but after that it wants to do it's studdering thing again.

What I have done
Replaced the driver side coil, (was told it was bad.)
Replaced the wires.
Replaced the plugs.
Replaced the battery.
Admitted that I am a much better computer man, than mechanic.
Asked you wonderful folks for help.

(The check engine is also on once the car is started; when the 'studdering' happens it flickers at me. I have tried to jumper TE1 and E1 with the key out of the ignition then turned to ACC to read codes, but I get no CEL at all. I have also tried the same with TE2 and E1 with no CEL either.)

Big Daddy

Any help at all? Any thing? Please? I know you guys know your stuff, help a country boy out here.

Neofate

iTrader: (1)

Hrmm.. interesting problem and it could be a whole host of things. Most of them not too serious.

This is what I can think of off the top of my head for you to check/do.

1) Clean TB - and intake tubing. (Carb cleaner)

2) MAF ? Clean? --Dangerous*Be careful you can mess things up even worse here*

3) Vacuum leak?

4) Stuck open EGR?

5) Change PCV valve.

6) Could air be escaping through your intake piping or somewhere right before it hits the engine? I would check the rubber harmonic intake tube.

7) Check fuel injectors.

8) Check engine compression. *Hopefully this isn't the problem.

Maybe that will give you some fresh ideas.

Good luck

Big Daddy

Thanks for the help man, I have learned that the EGR tube is cracked, I don't know if that would affect the reving of the engine though. It is such a pain because I can't get it to give me a code at all for the engine light.

PureDrifter

iTrader: (10)

check the TPS, especially if the car was recently serviced. after that, neo covered most of hte basis.

3UZTaco

I have virtually the same symptoms on my 94 LS400 and was wondering if you ever found a cause. I went through all the grounds and made sure all connectors were tight. Still nothing. I'm suspecting the ecu as it's the only common link between those systems. Any ideas???

slinky

My 1993 LS is doing the same thing as Big Daddys. Any information on a fix?

3UZTaco

A replacement ECU fixed mine. The symptoms you see are the ECU running in "limp mode". 93-94's seem more prone to failure for some reason.

mhlamin

bad ecu is my guess.

Rocan

+1 on that...