so im having abit of a boost issue...i notice today that my evo is alittle hesitant on throttle repsonce...so me and my homie went cruising around his neighborhood and i notice my boost will hit 18-19psi and then slowly drop to about 15-16psi as rpms increase...i cant seem to figure out why...it just started cause before it would boost 18psi and stay there...i was thinking that maybe the spark plugs were fouling out or something so i pulled two out really quick and checked them out...electrodes looked fine, the threads were burnt looking but the actual electrod and prong (whatever its called haha had a brain fart) looked fine...no build up...anyone else have this problem or anyone know what could be there problem...i check the vaccum line hooked up to my MBC and its fine and the knob on it is not loose or moving around...
any help would be great...im still kind of a noob at turbo systems...
thanks
-jared

 

Sounds like a boost leak somewhere (IC piping, couplers, BOV connection, etc.). Check that all the hose clamps are on properly, all vacuum hoses are still connected, and that you don't have any tears in IC piping couplers. Well, maybe not the couplers since it doesn't look like you have aftermarket IC piping.

 

could the spark plugs have anything to do with it...should i change them anyways...

 

How long have you had them in? What are they gapped to? Sounds more like a boost leak than an ignition problem, but I suppose changing them wouldn't hurt anything...

 

they have been in the car since i got it and ive only had it for a month...i dont know what they were gapped to i didnt check...i just pulled them out to see if they were done or not then put them back in...

 

Depending on how many miles you have on the car, you may want to change them. However, the stock iridium spark plugs (assuming they are still the stock ones) last a long time.

If you are worried about the spark plugs, check the gapping like buchnerj suggested. The issue is still more likely to be a boost leak given your description of the problem.