8850gt

well my girl is gettin sick whenever i start her up she starts fine. then then rpms come down after the initial rev and flucuate from 600 rpm to about 900 rpm. when this is happening the oil pressure gauge jumps around randomly, but never goes below the red line at the bottom... now if i put my foot on the gas bringing the rpms up to about 1200 it will stay steady. if i dont warm it all the way up to normal running temp before i start driving it will backfire badly in second gear when im accelerating. it even backfired in 4th gear yesterday and even after it warmed up it backfired. im not sure whats going on, was wondering if anyone else has had this problem before. i put new plugs, wires, and distributor cap in it about a year ago. im guessing its not that. its frpp 9mm wires, oem plugs and msd cap. also im not sure if this is related but the other day i stoped suddenly and my car stalled, when it did the amp light and the check engine light came on. i restarted it and they both went off... anyways if anyone has any ideas what it could be im all ears... btw its an 88 gt with stock engine, either 330k miles or 230k, but the previous owner said it was rebuilt.... i dunno any help would be greatly appriciated... thank you

1fastzook

I would check engine codes and do a cylinder balance test.

8850gt

the check engine light isnt on, so i dont know if any codes will pop up....

stang8689

I would clean the IAC first and check your TPS voltage

Joel5.0

The only way to find out is by running a DIY KOEO/KOER/Cylinder Balance Self-Test .... there are failure codes that will not cause the CEL to turn on, you should also verify the basic items...... fuel pressure, initial timing. Regarding the TPS..... if you don't have a TPS related failure, it's OK.... no need to adjust a non-adjustable sensor if the EEC sees it doesn't have a problem. LUK

Alero99

i guessing its a 1988

ther is no CEL on the 87 and 88s, there is no bulb in there from the factory...

run the KOEO KOER tests.

brentloftis

88, speed density or converted to MAF? Mine was doing similar things and eventually found it to be vacuum related to the hose to the MAP being old and rotted. Mine was a pin hole leak and it made the car run like crap and misfire here and there and buck around. Replaced the hose and presto runs like a champ... well a ugly partially paint stripped, old rotted tires, ripped top champ anyway

8850gt

its converted to maf, how would i check for the vaccum leak? it only does it when i first start up, and it doesnt do it everytime. sometimes when i start it up, it runs fine... and sometimes its worse than other times...

brentloftis

If its been converted clean IAC and MAF first, verify the spliced in pigtail wiring has not come loose. There are many ways to check a vac leak, everyone like something different. Professionals use smoke, some spray a shot of carb cleaner around suspected areas, I personally use a plumbers torch witha rubber hose.Iturn on the valve and move the end of the hose around the vacuum hoses and ports and listen for a change in the idle...

8850gt

ug, im not very good at doing this kind of troubleshooting think it would be a good idea to take it to my mechanic? just dont want him to give me alaundry list of stuff i dont really need to fix....