stumbling engine

[caniborrow50cnts]

Only during moderate and excessive acceleration, my gst engine stumbles quite harshly. It sounds like it is just misfiring badly. I can distintly hear a popping sound, like a spark from the wires. I have done nearly everything the repair manual suggests: Fouled spark plugs, fuel injection system component faulty, fuel filter clogged, ignition system malfunctioning, and vacuum leak check. I swapped the plugs, wires, coils, and injectors with the gsx I have, as well as replaced the fuel filter with a new one. The gsx runs just fine with them. I do not have a gauge to test the vacuum lines though. Would they be a likely cause of this problem? What other factors could contribute to the popping noise?

[ez1286]

It could have a boost leak causing it to backfire and that could be the popping sound you're hearing.

[l_eclipse_l]

What plugs did you put in and what did you gap them at...

[blk_srt]

boost leak. Do a test

[caniborrow50cnts]

I had a friend of mine drive it around last night. He says he can hear an echo on some buildings of what sounds like a tiny exhaust leak. My car has a 3" exhaust so it didnt cross my mind that it was a little louder. He suggested I should do a compression test and fuel pressure test, just to make sure those are not contributing factors.

[blk_srt]

while you are doing those do a boost leak test, actually do that first because I can almost promise you its a boost leak.

[ez1286]

A boost leak test is the easiest of those three the only probem is you need a compressor and not everyone has one

[blk_srt]

You can do it at a gas station or with a bike pump

[caniborrow50cnts]

i cant seem to find any instructions on how to do a boost leak test. I cant find any cracks or torn lines anywhere. It seems to be steadily getting worse on a daily basis.

[blk_srt]

www.vfaq.com