In the suggested mods for TPI cars, in the first step they include making sure the TPS voltage and the IAC vavle are set correctly. There's a link to click on to read how to do this but it doesn't work. I was just wondering how do I set these correctly and if these were messed up would it possibly cause these problems.

My car is currently being a royal Bitc#. For some reason it likes to missfire or what I think is missfiring. At low rpm's I hear a popping sound like small explosions coming from my engine bay. That's missfiring right? When the fuel hasn't fully combusted in the cylinder and the remaining gas combusts in the exhaust. Probably my headers. Well it only seems to do this when the engine is cold. It's really bad in the morning when it's been sitting all night. It is not, my distributor cap, rotor, spark plugs, plug wires, or O2 sensor. As I've already replaced these. I'm going to be taking it into a chevorlette service center tomorrow to do a diagnostics check because I have no idea what's wrong. If anybody knows what's going on with my car please let me know. I'd rather not have to pay the service center $85 just to tell me I need to replace this or that which will cost me another but load of money. Well thanks to anyone who can help, as I am most desperate at the moment. I'm trying to make this thing a decent street machine not something I get used to seeing the back end of as I'm pushing the car to the side of the road. Thanks alot.

 

Have you always been running those Bosh +4'z? cause i had a simular problem with crappy performance and popping like if i rev'd the engine when it would idle back down you would hear small misses, changed to a different set of plugs and it went away.

 

I had the chevy service center do a diagnostics check on my car and they said I need to replace the fuel pump? Is this hard they want to charge me $600. Umm.... does anyone think that's just a little hi? Could I do this myself, responces please.

 

And, no I haven't always had those plugs in. Around the time I installed them it started but I had most of the original's in when it did it though. I had changed out 3 I think then drove it around and it was doing that.