Small Block & Big Block Chevy Specific - please help

ok i guys, i dont know what all is going on with my car. out of nowhere it just started backfiring extremely bad this weekend. and also at no matter what speed im going the car starts vibrating horribly. however it runs just fine if i lay the throttle to the floor. any ideas or suggestions. any help would be greatly appreciated. thanks.

ok i guys, i dont know what all is going on with my car. out of nowhere it just started backfiring extremely bad this weekend. and also at no matter what speed im going the car starts vibrating horribly. however it runs just fine if i lay the throttle to the floor. any ideas or suggestions. any help would be greatly appreciated. thanks.


this happen to mine no to long ago on my lt1 camaro. I just change the spark plug wires out and the miss fire went away

hmmm i may try that. however the wires are almost brand new.

then if it not that try the coil

thank you sir, i still however feel slightly puzzled on the situation cause everything under the hood has basically about 3000 miles on it. i suppose though it might have not been tuned just right or something. but thank you for those suggestions.

sounds like spark plugs to me. If it wasn't tuned out you were prolly over fueling. If not the plugs, then I would get ready to pull the cam out and check it, but it really doesn't sound like the cam to me.

na i think the cam is fine. my conclusions right off were either that it was fuel or ignition. ha and now i really have to get it fixed cause the master cylinder in my truck just went out and i have nothing else to drive. but the car starts up just fine, however once that started it takes a few more seconds to crank up now. and it dont have a high idle start anymore... it will start and sit around 5-600 rpms and then after about 10 seconds goes up to around 850 and its fine. then the driving is when it backfires. touch the gas sounds similar to an intake backfire and when i let off or slowdown with downpull it has a nasty exhaust backfire. and when im just cruising its horrible i have to constantly take my foot on and off the peddle. unless of course i floor it. then it runs just fine.

Don't forget to really check out your EGR. I chased a similar problem with my daughters firebird and changed all kinds of things finally ended up being a bad EGR.

oooooo i forgot about the egr.

i had a vaccum line on my 95 lt1 in the wrong place when i got it and it would backfire like that. make sure everything is plugged into the correct places if you have access to another fbody like yours.

hmmm, well i can unplug my egr and the car actually runs pretty good. however something still seems a little off.