89 S15 Jimmy rough starts

Dawgmommy · December 11, 2016

My 89 S15 is starting rough / shaky but then idles great. Its in otherwise awesome shape. Its a 4x4 manual with a 2.8.

Doesn't matter if its cold, sitting a while, or hot. Just sporatic. Vacuum lines have been fixed. Air-fuel sensor replaced.

Someone has suggested replacing the throttle position sensor but I have no one to help me test it. Don't mind replacing without testing as I don't think it would hurt but would like input before I dish out the $30 if someone thinks its not the place to start.

Thanks.

Dawgmommy · December 12, 2016

So I replaced the TPS and am now getting a 22 error code = low voltage TPS circuit. It also is still taking a few tries to start - not as rough but catching and stalling.

Anyone?

Thanks.

seymourj98 · December 16, 2016

How's the connectors on the TPS look?

Dawgmommy · December 20, 2016

Hi. Well, my mechanic made some adjustment to the TPS and now the 22 error is gone but is back to rough starting. He put an ohm meter and ran the OBD scanner on it and everything was perfect except that the circuit would not stayed closed. He said he thinks the computer may have a bad ground and is suggesting that I get a new one (about $60).

He also had me replace the thermostat and ETC because it didn't seem like the engine was heating correctly (because the main hose off the engine didn't seem hot). I don't think the thermostat was opening or something but anyway, it didn't hurt to replace them.

So, at this point it usually won't start unless I give it gas and then it sounds really loud and coughy for a few seconds before leveling out. Now I'm wondering if a bad ground to the computer could be the problem like my mechanic says?