Man im lost, I changed the oil pan in the z28 and no leaks! I ran cheap oil and cheap filter to test for leakage. there was none. I let the car cool off over night and drained the cheap oil and put the good stuff in with a good filter. Tried to start it up and take her around the block and I had 2 header ignitions or back fires before I could get it off the ramps. I checked the plugs with a plug tester and im getting good spark. Im going to go get new wires today b/c I noticed that they have some groves in them. Just to eliminate that problem. I don’t know what else to do. Maybe I jumped timing. I also I started the car and held 2 white pieces of paper at the exhaust tips. when it back fired it was on the passenger side. keep in mind that I have true duals no x pipe or y pipe. I pulled the valve covers off and everything looks good under there. one more thing it runs rough in idle. when you put it in drive or reverse it feels like there is a hefty cam in it and that’s when the back firing gets bad and the whole car starts to shake. I need some help b/c im pretty lost.

 

Have you had the wires off? Maybe you got one of the wires crossed. Had the same problem last week. It was # 6 and 8. I thought had them right so I double checked and sure enough they were wrong. Just a thought, not sure if thats what it is but you gotta start somewhere. Its sound like its fire related thou. Also could be an injecter sticking or the distributor. Is it all stock or mods. installed?

 

yup, you and me are in the same damn boat, im about to just pull all my wires and replace them and see if that helps.

Oh and i just put a brand new opti on mine.

 

May not be the problem but I had very rough idle when in drive and reverse, and a few backfires and really sluggish. Come to find out it was the opti, I would start @ the wires then to the opti.

 

well i changed the plugs and wires with some cheapos and it runs fine so im not sure what happend but, here is a pic of the plugs as they were when they came out no cleaning. thanks for the help.