hi guys just need some help what would be causing my car to backfire under full throttle only does it real bad when I been cruising for a while with no taking off as in highway driving.

I have flash tune boost is 10psi everything else is stock thanks guys

Justin

whats the Plug Gap?

no idea mate that's what I thought as well almost sounds like its fouling the plugs

Spark tends to blow out at stock Gap when the boost is turned up, generally .75/.8 is the go.

It could also be lean back fire, has the car been on a dyno, Please dont say its a Generic tune...??

(oh and when you reply to a post directly before your please use the add reply or fast reply box at the bottom of the page. if you use +reply on the post it quotes the post. No real need to do that if yours is the next post inline

yeah its been tuned on dyno at tdr in geelong they did mention maybe changing the plugs they said the iridiums are crap and just get normal ngk ones but I dont know how correct that info is lol it doesnt backfire all the time which is weird I thought it was fuel but want a few opinions got me stumped

If they are telling you to change to a normal plug over the standard ford iridium then I'll say its a lean backfire! lol

Close those plug gaps up though to .75 or smaller first and see how you go.

thanks guys

keen to hear how this turned out?

Well I've had a few dramas with the boost solenoid clicking when ignition on so I've had to put the stock tune back in it that's the only way the car runs

the clicking is just an adjustment in the tune, get your tuner to adjust it when you fix the problem