Hi all, I have Evo 7 with 2 maps, 300 and 340. I have started noticing that the car does not accelerate and do not passed 6000 rpm and cuts on stop at 5000. Also I hear a loud pop noise coming from the exhaust when accelerating. Any ideas of what may be the problem?

Thanks in advance for your help!

 

Get some new plugs. Gap them down to 0.020" and then report back.

 

Thanks Ev0ikon for your prompt reply. I have the standard ones on NGK IGR7A-G with a gap of 0.028" (0.7mm). Should I put the same type? or because the mapping do I need a different ones?

 

Sounds like spark plug blow out. I think that gap is too big, I'd do what Ev0ikon said.

 

Try to gap them down to about 0.5mm. If they are Iridium be careful not to damage the tip.

 

Do a boost leak test, its such a common issue that it should be the first thing anyone does when diagnosing a problem with evo engines.

 

Ran into something similar, it was one of my intercooler pipes that had a tiny crack in them that would allow air past at a certain RPM. See if anyone close by will do a leak test for you.

 

thanks all for your input. When bought the car it has NGK BR8EIX on and I changed them for the standard ones. At weekend I will put back those plugs and see how it goes. Also will check will leak test. Let you know the outcome

 

Aren't 7 NGK plugs too hot for this power? I would stick with 8's.