Backfire?

[PacmanTravis]

Ever since I got my YoDude, my cat has been backfiring. I also gutted my cats around 2 or 3 weeks ago, and the back firing is happning more. Now, I dont MIND it really, I just want to make sure that its not f@cking up my car. It usually happens when I am engine breaking and the sort or when I slow down from a high rpm. I.E. - Going 45-50 in second and just letting go of the gas, it backfires.

Any ideas?

[Kaiser]

Either you have a vacuum leak somewhere or you have a real fuel issue. I vote for vacuum leak. Check all hoses after the maf and attached to the manifold. You are losing metered air somewhere and going rich when you shift.

[Kaiser]

Especially the EGR, it could have gotten knocked around during install of the new exhaust.

[rista]

my car backfired one time so far. i have an automatic tranny, and when i floored it, the rpms went all of the way to 8000 rpms!!! (shouldn't there be a rev limited on this thing, i have not got anything done to the computer) when it finally shifted it give the tires just enough time to grip the pavement and when it did, it put a terrible load on the engine and went 'KA-BANG!!!!!!' i almost **** my pants it scared me so bad. but all the bystanders that were watching thought it was pretty cool. i have gutted precats and i don't have the mil's on yet, so i think i may be running rich (am i right on that, or should i be running lean?), and i think that could have contributed to the cause. but to answer your question, i think it's because you have no backpressure, but i don't know, just an educated guess.

[PacmanTravis]

So, check for leaks more on the induction side (uim,tb,maf and the such) or more of an exhaust leak?

[Kaiser]

check for leaks more on the induction side (uim,tb,maf and the such)

That is where I would look. There are 2 egr hoses by the throttle body that I would definately check.

[PacmanTravis]

Well, I just did a visual check and turned on my car and checked for leaks while revving the engine...and I found nothing. All i could hear was the slight whistle of my intake, but thats all. All the hoses going from the TB to the UIM and the such are all nice and tight.