LS1Steve

I've been through a world of fun with my 3vze recently, and finally got it running perfectly after a compete tune (plugs/wires/cap/rotor/cat/o2) and a much needed TPS sensor and timing adjust.

It ran like NEW for a few weeks, but now it doesn't want to idle. I can start it (rough to start at times) and get it out on the freeway at full operating temp....and when I put in the clutch the rpm's go down to zero. This happens about 80% of the time when on the road. I've stooped to having to pull out of gear, keep revs up with right foot and brake with the left most of the time (but not always). The times where it does want to idle, it does so smoothly at 650rpm.

One funny thing it does, is that when I keep the revs up (while waiting at stoplights), I have to keep it at 2k or higher. If I give it just a slight amount of throttle, like between 1k-2k, it will start surging between like 500rpm and whatever amount of throttle I have it at. It just keeps dropping off like once per second.
When I am in gear and driving, it acts normally with full power at all rpm's.

Did my TPS go bad again?

Cyberman

I had that problem, when I had a vacuum hose come off. Might want to check all the air lines, and make sure there's a good seal at the throttle body.

LS1Steve

I think the problem with the surge will probably address the idle shutoff, any help?

Can't keep rpm within 1k-2k.... ie: if I depress the accelerator to 1500rpm, it will jump between about 500rpm and 1500rpm back and forth once per second!

TPS?

LS1Steve

its getting desperate.... my battery isn't the greatest and i've required a jumpstart once now in the middle of traffic. It runs GREAT but won't idle!!!

thook

Are you sure you tightened the TPS down well when you replaced it? IOW, you haven't lost the adjustment due to rattling around?

Maybe test the TPS at the ECU connector side to see if there isn't an issue in the wiring to the ECU. Same procedure for testing the TPS at the TPS, only you might need a hand to keep the feeler guage between the throttle lever and stop.

Also, check your airflow meter. A while ago, I'd had problems with my 3vze auto very similar to yours and found it to be the meter. The only difference in behavior was with the fact that you never let up off the throttle when driving because, of course, you don't have to clutch it to shift. So, I never had drop offs while accelerating or otherwise.
But, whenever I came to stop or had to slow down, the engine would begin to faulter and even die in many cases.

BTW, 650rpm is a pretty low idle......smooth as it may be.