weird idle problem

[Kenny32391]

I just had a rebuilt engine with 5,000 miles put in my 98 gs. My battery needs to be replaced but everything still turns on and the car will start to turn over and comes on but dies as soon as it starts. It will start occasionally but i have to keep my foot on the gas and when i rev it up its back fired a few times. I got it back last night and when i started it the idle would go up and down from almost dieing to around 1000 rpm. It is the worst when my lights are on. Please help i dont have another car so I needthis fixed asap. i already nhave searched for hours and i cant seem to find anything that fits my problem. Im going to replace the battery but i dont think that is what the problem is.

 

[urmomsaniceguy]

have your alternator tested. also try picking up a MAP sensor from the wrecking yard. also o2 sensor mine did the same. and i replaced all.

 

[Kyle97-clipse]

+1 on the alternator also do check the MAP sensor with a multimeter because that also does funny things

 

[#40Fan]

Weird things happen with a weak battery and/or alternator.