BigBadGTA

So I have a 1988 GTA with the L98 engine. Engine is all stock with 86K on the clock. The past couple weeks I have been on a mission to remedy a ruff idle problem its had since I bought the car two years ago. Last week I bought a brand new idle air control valve, and when I installed it I took off the throttle body to clean everything real good. It still didn't run as smooth as I would like it to so I adjusted the minimum idle air, throttle screw, and the throttle position sensor on the throttle body. The car idles at about 4-500 warm when in gear and runs pretty smooth. When its cold it still runs like ****. I started it up when I was leaving school, and it almost stalled when I put it in reverse to back out of my spot. What the hell else can I do to try and make the car run better? The plugs are still clean and good, I just replaced the wires and cap and rotor. fresh oil change... The MAF sensor is only 2 years old.. I am out of ideas, this car just does not want to cooperate with me and I am starting to get real frustrated.

Base91

iTrader: (1)

I think your idle should be 700 on an 88. ??? The '87 was lower.

BigBadGTA

Well I adjusted it so the idle is about 700 when its in park or neutral, and 450-500 in gear. It used to be lower than that, It was about 350 in gear, and 500 in neutral before I changed it. When its cold it just runs like ***, it feels like the engine doesn't want to go when you put the pedal down to get moving.

Base91

iTrader: (1)

Putting it in gear shouldn't drop the rpm that much. Sadly sounds like more investigation is needed of the usual suspects. Plugs, leads, sensors injectors etc. etc. etc. I recently went through it and of course it was the injectors. You hope it's the cheap easy stuff but....

Air_Adam

Have you removed and cleaned the throttle body itself? Including all the little passages? And the MAF? That can make a HUGE difference if its all carboned up. Made a big difference on my LT1, which uses basically the same throttle body as your L98.