ChrisS95TA

Well, this has happened twice in the last month. Happened yesterday, both times I saw going in first at about 1200 rpms and I heard a pop or something under the hood . I parked it and listened to it for a while from all sides and close to the valve covers, sounded fine. Ran WOT to 5700 RPMs and 0 knock retard. My maintenance info is in my sig, any ideas as to what I should check? PCV or EGR valve maybe? Thanks for any tips, dont want to have to rebuild just yet

kmook

When mine did that it was doing it a lot but the car was also running real bad in general. In the end it was bad o2s for me.

Megalis

Mine pops all the time, but it happened right after I took off the cat and put an off road pipe...I think that may have something to do with it


So who knows maybe it's your cat not doing what's it supposed to. Sorry I can't help you out more.

ChrisS95TA

Hmmm, my cat was clogged and made my car start overheating about 15k miles ago so I had a new GM y pipe and cat installed so that should not be the problem.

Could maybe a clogged EGR system cause that? Trying to narrow it down before I do any work. Thanks for the help.

Megalis

Well that may be it, but who knows. Oh and if you look at my sig you will notice that I changed out my Y pipe also, at the same time I put the O R pipe on there Too! So maybe the problem lies in the Y pipe and cat set up combination. We both did similar things with similar results.

I will tell you that is the problem for sure if you get FIRE! out your tail pipes. I rev the engine high like 4k+ rpm's then when I change gears ( from 2nd to 3rd or 3rd to 4th) it pops real loud and 2 ***** of fire come out! I would have it changed but you know what, I have been told to many times that it looks cool. It uses up more gas, but I think it's worth it!

ChrisS95TA

Revs to the limiter and never makes backfiring sounds or fire or anything. I am stumped, such a weird problem and it sounds/feels so bad like if I had tried to gas it at the same time something could have broken. EGR looks like a PIA to get off at the manifold mounting point, the hose looks brand new silver I wonder if they changed that when they did my tuneup.

Y pipe and cat I ordered from Dal, genuine originals so that cant be the problem I dont think. No weird smells or noises from cat either.

btchincamaro

I put some 87 octane in mine and tried to pass someone on the I-state in 6th gear. Big backfire through the intake. Dont use the cheap gas anymore. 89 is min. for me.

ChrisS95TA

Never had anything but 93 in my car, ever.


Maybe a bad batch of gas? Or maybe I was lower than I thought on gas? I usually try to keep my tank atleast 1/4 full which is about 1/2 on the gauge but sometimes if I am stupid I dont pay attention and it goes lower. Hmmmmmmmmmmm....

Rice Killer87

a bad/fouled plug will cause a backfire too.

being an LT1,i hate to tell u this,but thats something to check

ChrisS95TA

Bad or fouled plug can cause an intermittent intake backfire?


Just had the plugs done within 1000 miles, dont want to pull them to check since everything is running fine. Cant wait to put on my MAC headers so I can do the plugs and wires myself

Rice Killer87

yea man,i had a fouled plug in my car leaving school 1 day,and if i was cruising along and then give it some gas,it would stutter and backfire.

good luck on finging ur problem