Hello everyone!
So I have replaced my TPS 3 times now. I am pretty good about letting the car warm up before I drive it and if I have to drive it cold I take it pretty easy.

Last week my 91 vert had a rough time firing up in the morning. It's possible maybe I hit the gas peddle getting in the car or pressed it getting out the night before. After a few tries and wrapping out to 7k rpm's for a solid 15 seconds it held its idle and (what I believe) to have burned up any excess fuel. Ran fine and dandy...

Wednesday I was just driving, normal acceleration, fourth gear, I received a fuel cut or tps giving way again. I dumped the clutch while moving still, she fired back up but I had to rev it up to 7k and hold. Ran fine for the rest of the day.

Yesterday morning I on the way to into the office, I didn't have time to warm the car. First gear, I started rolling and it cut again. I fought it, got it to fire up and fought to get it to 7k. After getting there and holding, it ran fine.

What am I fighting here? Bad luck with TPS? Heavy carbon build up? Could a fuel injector just be leaking? The car does smell like it runs rich. Could this be an electrical battle? While I am going on here, my RPM's at idle do bounce a little. 500-900rpm, some times it just holds steady. Could it just be a bad fuel pump relay?

Any insights? I am going to go through tomorrow with some carb cleaner, see if I can find an intake leak.

Thanks in advance!

Chris

 

First check for the vacuum leak as you planned, than i would be getting tge injectors cleaned

Actually, after you check for a vacuum leak, do a compression test just to be on the safe side, if you've replaced the TPS 3 times with the same result, i highly doubt thats your problem

Another good possibility is your coolant sensor for the ECU could be giving the wrong reading

 

Are you adjusting the TPS after installation? It should be adjusted on a warm engine, making sure the fast idle cam on the Throttle Body is disengaged.

I would think a vacuum leak wouldn't be so intermittent, but I'm not sure.

It seems like it does it when warm or cold, under varying conditions. Like a bad connection. Wiggle any wires or connections, especially the spark plug wires. See if the problem shows up.

Also, if you have the problem while stopped in a safe place (parking lot, driveway), don't fight it. Let it die. Then, when it's cool enough to do, remove the lower spark plug from each rotor and see if any are wet.

Another thing is to check for spark when the car runs bad.

But like others said, an intermittent injector starving the engine of fuel, or getting stuck open and flooding it is also possible.

Do more diagnosis before throwing money at it. Maybe a few more members can help with more ideas.

 

Pull the codes.. Doubtful the TPS will make it die while driving down the road. Also doubtful an injector is acting up, they generally work or don't. Your S5 will have the codes stored, and your fuel cut is likely Limp mode from your OMP or ECU going south.

 

Well it wasn't a vacuum leak. I sprayed every house I could find and sprayed around all gaskets area's I could reach on the intake side. I adjusted the idle each time with the motor at operating temperature.
When I bought the car there was one single hose that was disconnected and the car ran smoother with the hose disconnected, idle held steady, a little high at 950ish. I think it came off the cruise control unit to the T adaptor behind the throttle body.

 

No. I'm was talking about adjusting the tps by turning the screw on the throttle body that relates to it.
But yeah, as mentioned, a tps being bad or not adjusted shouldn't cause all those problems.

 

yeah I adjusted the tps with a multi meter. spark plugs done recently too, oil change. I will try looking for loose connections tomorrow after work.

Thanks everyone

 

Check your airflow meter.

 

Here is a video of my rpm's acting up a little bit. I replaced the thermo sensor and the car hasn't just died on me since( knock on wood)


I assume its a bad ground or alternator starting to go south

 

Ok -
So it's been a little while since I've really had this problem. I thought that this had gone away. Quick little history (also to remind myself what I've done so far). I have:
-replaced the TPS twice ( and adjusted )
-Coolant temp sensor
-Alternator upgrade to s6 w/ double v
- spark plugs & wires
- lead igniter
- oil change 1000 miles ago and check every fill up
- I get on it at least once a day as recommended

Last week it started cutting out on me again. Once after a trip across town and back. Again the following day but real bad like. Every couple seconds. Gives me no engine codes besides what I had posted before. Today, again, I got in it just to see what would happen. She jumped on with no problems for an hour.
The only difference between today and the last couple days I drove her, was today is rainy, the other days were nice out about 65 degrees. Does this shed any new light on anything?


Thanks in advance

 

What is the sound of rushing air in the video. Is that the fan/AC being turned on?

 

yes it was. I thought it was weird that I turned the heater on and the rpm's dropped so far. I upgraded to the s6 alt since the video was posted

 

And when you turned off the dash lights the rpm seemed to stabilize although it was at the very end of the clip and I might have been seeing things. In any event, the BAC is responsible for holding the idle at 750 when under load, such as the heater in your case and the lights thus check the operation of the BAC.

 

Awesome will do. Any thoughts on why she has been dying on me while driving?