I'll get to the point. I've got an 88 vert. My idle is really low and rough. It sits at 500 rpm and dips and raises 50 or so rpm intermittantly. My gas milage is horrible at about 60-70 miles to the half tank, and you can smell fuel in the exhaust. My TPS is set. I also have a second one with I've also tried and set. Both sweep cleanly from 1.0 ohm to 4.7 ohms, all day long. And the idle adjustment screw doesn't help.

But with my TPS unplugged the idle raises up to 1000rpm and smoothes out dramaticly, but still burbles a bit. But now the idle adjustment screw does have an effect and I can lower the idle all the way down to almost stalling and up a few 100 more rpm. My milage also improved exponentially to about 100+ miles to the half tank.

And finally the only time my idle is just about perfect. (Compared to my friends 88 vert.) Is when the A/C is on. Whether the TPS is plugged in or not the idle goes completely smooth and raises or lowers to the proper rpm. Clearly that means the BAC is working. But I tested it any way. It was at 12.7 ohms.

I've been driving around with the TPS unplugged for a few weeks and haven't seen any problems other than hesitations when driving around. But that's expected.

Has anyone had similar problems and fixed it? Is it the TPS or is it something else?

 

hmm strange....

stock intake and exhaust?

 

Yeah, stock intake. But the Previous owner hacked up the exhaust. He had the second cat removed with a larger diameter pipe going to a high flow cat, to the stock Y-pipe, then to some jank *** glass packs. Sounds and looks, horrible it's getting replaced soon. But do you think that could be part of the problem?

 

Ok, I've got a few more symptoms that might serve helpful. Like I said before, with TPS plugged the idle is really low and grumbly. Like it's groaning. I try and put up a sound file tomorrow. Also, it's got some pretty funky high rpm hesitations, but never in first gear only in 2nd sometimes and 3rd always.

Man, this sucks.