my 03 EVO is okay until the turbo kicks in. once it kicks in, the car backfires and sputters feeling like the cat back just wants to fall off.

it started after i changed the plugs so i changed those with some stock iridiums. it helped a little.

any help would be greatly appreciated.

 

possible boost leak

 

Sounds like they are gapped wrong, what did you gap them at?

 

Over boosting maybe... Do you have a boost controller?

 

you cant gap platinum plugs.

 

Actually the stock plugs are iridium...and yes, they can be gapped....

To the OP....try a boost leak test and also gap them plugs down to .025

 

You know I had a similar problem after I switched out my UICP, Turned out there was a pinch in the silicone coupling between the sections of the UICP. Went way rich and started kicking and bucking like a pissed off gelding with 50 mares around. I also agree with checking the gap on the plugs, you can gap iridiums its just that you have to be extrememly careful not to damage it.

Josh

 

probably checked it already but if your mass air sensor isn't connected all the way this will happen, did it to me once when i was changing intake pipes?

 

Sounds to me like a hose is off and you have a bad boost leak. That will cause the car to run insanely rich and do the things your describing.

 

one of your coil packs is probably going- or your MAF is going- if you have any friends with evos switch them up- if its your coil packs i have a set for sale let me know

 

THANK YOU all very much!

I took Alan678's advice and told my buddy to gap the plugs at .25 and that did the trick.

Mitsubishi had told me to gap their stock Iridiums at .45. Those SOBS!

Again thank you all, and a big thanks to Alan678. Y'all are the best!

 

No problem man! Glad you got the car squared away!

 

did you learn that putting iridiums in your o so totally rad mazda? , did your nos or underglow experts tell you that

 

Alan is Evo-King.

 

lol...underglow experts