ok big problem need serious help!

Bacondoggy

Registered User
I have been away in the 82nd airborne so I have not had time to fix my car. but these are the symptoms:
first of all it is a 91 sc 75k about 4-5k on the engine - all new parts. maf is good, new IAC.

you start the car it seems fine after about 5 seconds (most of the time) it seems like the computer runs a test and pushes the rpm's up to 2100 and it stays there... about 20 seconds it calms down and goes to about 900. now to main problems. #1, when driving, if you put the car in neutral, it idles around 2000 rpm, until you come to a light or stop then in about 5 seconds it will slowly go back to normal idle. #2 when you step on the gasand its below 2000 rpm (in any gear - even 5th going like 45), the car stutters and dies. as you step on the gas the rpm's will go down and you get NO power at all. the only way I can drive it is to downshift and rev the engine alittle to get it to go. once around 2000-2200 rpm the car will kick you back in your seat and seem to work fine. at WOT it seems fine after the madness. I am sure if it is doing all this, there is HP being sacrificed even at WOT. Me and a buddy tested it a while back and it came up with a code saying both banks reading lean. the O2 sensors - one is brand new and the other one is fairly new if I can recall right. I am very frusterated because I have no idea what is causing this. the fuel pressure is normal, and the fuel injectors SEEM to be intact. One was brand new (the ceramic end was chipped off very slightlly when I took them out on the rebuild so I replaced it.). any ideas would be GREAT!
thanks guys..
Mark
 
Tps

i would try checking your tps voltage, I had to do this after a throttlebody install, Mine was acting up like yours did, it didnt shutter and die, but the other symptoms are exactly the same, worth a shot. Mike
 
the tps... well I have 2 I am not too sure about that because a buddy of mine knowledgeable in sc's actually kinda drilled out the one side of the tps and turned it so it got to the right voltage (what is it I actually forget now). I know he ajusted the throttle plate and the one screw you arent supposed to ajust lol. so I dont know if that has anything to do with it... I think he had to do all that to get in in the voltage range...
 
I BELIEVE (As in not 100% sure) it is 0.96 - 1.00 volt....that is not for sure..
Sounds like a vac leak or other unmetered air getting into the system. Check your IC tube joints and vac lines. Try the un-lit butane torch trick with car idling. The "O2 running lean" codes are usually ghost codes from bad info being sent to the eec via other sensors and usually not the fault of the O2's themselves. Also had a similar problem that ended up being the DIS one time, but the idle problem leans me towards a vacuum leak as I have experienced more than once... :rolleyes:

Did this start after taking anything apart or messing with anything?
 
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