Just recently went through an alternator issue, it went bad (putting out 18v) and then the rebuild was bad (18v also). So after I got it back the 2nd time and put it back on I went for a test drive and stopped at a nearby station just to put a couple of gallons in. Left the station and not long afterwards I was cruising along and the car started bucking like crazy. If I gave it just a little gas, or let off, it cleared up. It idled fine and could go WOT, accelerate or deaccelrate with no problems. Just trying to hold a steady 45 or 55 MPH in 4th or 5th and it would buck like crazy. A couple of times it even stumbled( (?) as in it felt like the car just lost power for a second or two and then kicked back in running. No warning lights or anything would come on as in the car completely shutting off. Then I wondered if it was bad gas so I went to my normal station and filled it up and the problem went away. That is until last night and it's started doing it again even with 3/4s of a tank left.

So I've spent some time today searching and have found similar, but not exactly the same, issues and have come up with TPS, fuel pump, injectors, grounds and a dozen other suggestions from people. I'm also wondering if the alternator putting out 18v could have screwed something up. But what's throwing me off is that it cleared up and was fine for 3 weeks (not that I drive it that much) after filling it up until last night. And for what it's worth the alternator is putting out correct voltage.

So before I start tearing things apart... I thought I'd see if anyone had any thoughts.

 

I would suggest checking the terminals in the connector going to the TPS. It's easy to access and if it's simply those terminals are corroded it's a simple fix, clean or replace the terminal.

 

Not a bad idea. Going to check the battery also, then the TPS and after that.. work my way through whatever I guess.

 

Finally got around to checking the TPS this weekend. From what I can remember the narrow side read 2.Xk closed and 8.Xk wide open. On the full side it read around 1.2k closed and 4.Xk wide open. So, I tried to adjust the screw and couldn't get it to budge one way or the other, even after soaking it with PBlaster. Put it all back together, cranked it up and it idled fine and seemed smoother holding it at different rpms just sitting in the driveway. So I decided to go for a drive and of course it wasn't bucking anymore. But, if I let off the throttle slightly still holding speed it would gurgle (best word I can think of) and when I came to about my 3rd or 4th stop light the car wouldn't hold idle, it would just die. I could hold it at about 800 to 1000 with the pedal and it idled fine but if I tried to hold it anywhere from 1500 to 3000 it started surging up and down. Came back home let it sit for a few mins then cranked it up and it idled just fine. Went for another spin and it did the same thing again, gurgling and dieing. Runs great otherwise!

So from what I understand it should be reading on the narrow side .8k to 1.2k closed and 4.Xk to 6.0k wide open and anything above 6 is a bad TPS? And I'm guessing if I could have gotten the screw to turn I could have gotten the closed setting close to spec for both maybe but doubt it would have helped the narrow full setting. Now that I think about it either the narrow or the full would sometimes read correctly when checked in the closed position when I was messing around. And even more crazy a couple of times the cam got stuck against the upper intake manifold when I had the throttle wide open. But anyway, I'm guessing I have a bad TPS and who knows what else.