Ok, I have had some problems with my Z28 since I bought it. At first it would sputter and stall when you first touched the accelerator, but if you hammered it, it would leave two 50' long marks on the pavement. I replaced the oil pressure sender and changed the oil and that seemed to fix the problems. Now, after i drive it a bit in the heat and the engine heats up, the engine will sputter and backfire in moderate accelerating conditions. I also notice there is a "chug" noise coming from the drivers side part of the engine ALL the time. Ive already spent over $2000 in repairs in the vehicle. (new transmission being the most expensive).. anyone care to enlighten me on what is the cause of my next repair? The car is completely stock.. It has 73,8XX on the clock and i believe im the second owner. I want this problem resolved before I start modding it (cai, magnaflow exhaust, etc).

 

I had a seemingly similar problem recently. I pulled off the TB and cleaned it real well mainly focusing on the IAC motor and passages. I made sure not to move the pintle. I also cleaned the MAF while it was out with Q-tips and rubbing alcohol. I was surprised by how much build-up it had. Be careful if you clean the MAF it is pretty delicate.. but it won't self destruct upon touch like some people suggest. I did this about 4 days ago and it hasn't had idle and moderate acceleration stumble since.

 

OK, took off the intake elbow and well pretty much all the intake assembly from the elbow to the airbox(appearently the only things holding the intake assembly to the car was a hose and two connectors for the maf and some other sensor in the intake elbow.) The TB was pretty dirty and it was pretty hard gettin the qtip to form between the small spaces, namely where the idle bypass valve is under the tb. I dont know how much that helped yet. I havent driven the car enough to find out.

 

Hmm... Maybe I didn't word that well enough... I just cleaned the MAF wires with a q-tip and alcohol... For the throttle body. I took it off the car and removed the IAC motor and TPS sensor then sprayed it down with TB cleaner. I cleaned the IAC motor itself with an old toothbrush and TB cleaner.

 

Haha.. Yeah.. that explains it alot better.. unfortunately im gonna need to find the time to remove it from the car.

 

Nah, the TB is really fast to remove. I had mine off cleaned and back on the car well under an hour. It is only 4 bolts 2 sensors and 2 hoses.

Well, that is assuming you have already done the the TB coolant bypass. If you haven't you either have to drain the coolant or pinch the line near the TB.