My car has been backfiring under WOT lately since the weather dipping into ~40 C. When I step on it and the rev goes pass 5k RPM, I can hear "bap,bap,bap" coming out of the exhaust, sometimes a loud pop coming from the engine and I lose power temporary.
The car was pro tuned this summer in 80 degree weather. Do you guys thinks I just need a retune? or is it something more serious?

EDIT: My car just has the basic bolt-ons: full BR exhaust (straight pipe all the way), BR IC and pipes, Walbro. My CEL is on because I still need to put a O2 spacer on the rear 02 sensor

 

change ur plugs sir..

 

^Will try that tomorrow. Thanks.

 

plugs are a good start, but with it being cold its probably over boosting. keep an eye on the gauge once when you do it. Mbc? i know my evo on a stock solenoid in the wisconsin cold would hit 30 no problem. even with a mbc it will creep up in the cold probably have to turn it down a tad

 

Who tuned the car?

 

Kasey @ HIS Motorsports in NC.

 

More than likely it's your plugs like said above. With the colder temps my car was over boosting slightly and would pop a few times at full boost. Pulled the old set of plugs, there were a little fouled, dropped in some non protruding plugs and no more issues. Gap on the old plugs opened a bit and I have a slight boost leak so that didn't help either.

If plugs don't do it test for a boost leak.

 

It was the plugs. Thanks for the help.

 

Yeah haha friend had same problem and plugs helped aswell