sounds like you must be pretty near getting that problem nailed...

Have you checked all the plugs for colour to see if the fuel combustion is the same for all bores ?

 

Evan,

Seriously? LOL....You are such a F#%^&ing character....

 

This is going in a totally different direction than everyone else but if the TPS doesn't turn out to be your problem look to the head gasket. I had very similar issues with a LandCruiser and after much head scratching found a very small HG leak.

 

The HG is relatively recent. Last year. No real reason to think it failed.

 

not the tps...dammit.

 

NOW go back to my post on checking the injectors. I don't care who you had to clean and check them. I made the same mistake of ruling out injectors after I had mine serviced and they came back with a good report. Many parts replaced and it turned out to be an injector. Harbor Freight has a Cen-Tech infrared thermometer on sale for $29.00. It will help you diagnose a misfiring cylinder.

 

OK.

 

of course it isn't the TPS its simply a switch and potentiometer and is not effected by temperature. It either works or it does not .

everyone told you that the TPS couldn't make that much difference to running.

Unfortunately there are too many folk on the net that know absolutely nothing about the Bosch ignition and injection control system but are only too happy to make silly suggestions that confuse the issue.

 

I reached the end of my rope, and took the car to a shop. We have ruled out vac leaks, and fuel deprivation. Also put a different AFM in to see if that helped. The other AFM made the car run worse.

We don't believe it is a bad injector. Systematically checking all sensors in the fuel injection change, to see if any are bad.

As a recap...the car is OK cold. Good acceleration, good idle. Once warm, the engine stumbles, and has no power off the line or when accelerating.

 

sounds like your spannerman is doing the same as you and desperately testing things at random.

You need to follow a troubleshooting guide systematically .

To eliminate fuel delivery with an intermittant problem such as this I would install a fuel pressure guage to the fuel rail and put the gauge in the car. Take a run and observe the pressure guage when the car misfires.

That simple test should either eliminate or confirm the fuel delivery being the source of the problem or not.

You still haven't answered the question whether or not you have cleaned and checked all the earthing points on the car have you !

 

Pete, whisky tango foxtrot, over?

Sitrep?

 

Pete, systematic diagnosis. You said it runs fine when cold. So that would mean that whateve the problem is has to with something that does not come into play until the car is at operating temp. The TPS does not change function based on coolant temp. When the coolant is below 90 degrees, it is in "open loop" meaning it goes on a preset fuel/ignition timing map. Once the engine is in "closed loop" it starts to look at air volume (air flow meter and thermometer that is in it) The DME derives air flow mass from a volume@temp reading. Then looks at the exhaust gas content to determine if the mixture is stoechemtric 14:1. If it is rich, it will close the fuel injectors early, lean it will keep them open. Ours fire injectors 1&3 together and 2&4 together. BTW did you ever change the DME coolant temp sender? Also of value is testing the injector pulses, you can check this with a NOID light. Or when the vehicle is at operating temp, start by disconnecting one injector at a time and see if the problem changes. That test could fail, if an injector is stuck open it will not show a change when unplugged.

 

I'm gonna throw out Fuel Pressure Regulator. $60 @ any autozone

 

If it isn't the temp sensor I'm going to insist on a pressure test...

 

I'm not wasting any more of my time. OP hasn't bothered to post back in 2x weeks or answer questions or even offer any thanks !.
guess his car is running ok now huh?!

doh Peanut eats another bowl of Humble pie (see later post by Pete . )