Jumpy timing

[ozzyleven]

My 94 3.0 has been running rough lately and the idle jumps around quite a bit. Its pretty much gutless at certain RPMs and sounds like its working too hard. I've checked for vacuum leaks (unlit MAP torch) and there don't seem to be any. Everything is connected and routed right. I checked the timing today and the timing mark jumps around a lot, idle moves with it. I can't seem to get it set right. Sometimes it slows down to the point I think it might stall and then picks right back up. Jumpering the TE1/E1 does not slow down or stabilize the timing, although I know its connected because I get the proper dash lights.

I've been reading that a bad TPS can cause the timing not to re****, but would that also explain the jumpy timing/bad idle? Anyways, I plan on checking the TPS this weekend but it sounds like its something that will piss me off. Might sound like a waste of money, but if I get a new one and throw it on, will it be adjusted right out of the box? Or will I need to mess with that too? Its been a bad month, zero patience left for anything, and since the Tundra is still being repaired (5 weeks in the body shop and counting...) its my only set of wheels. Any other things I should check? Or is the TPS a pretty sure bet?

 

[KidVermicious]

A new TPS out of the box will need to be adjusted. Hit up 4crawlers site for TPS testing instructions, make sure yours is bad before you spring for a new one.

 

[ozzyleven]

Bah, thats not what I wanted to hear. I get a discount over at the dealership now (thanks girlfriend) and it was only going to cost $70, but I guess I'll just have to suck it up and do some actual work. So Kid, do you know if a TPS causes jumpy timing too? Been searching and can't find a definitive answer.

 

[KidVermicious]

Not a mechanic, but I know a bad TPS can do funky stuff that you wouldn't think would logically point to it, and as far as I know if your idle doesn't change when you jump the test port, that's a hard isolation to your TPS signal. I'd test it out to make sure, but it sounds to me like there's something wrong with yours, and it needs replaced even if it isn't causing your erratic idle.