Same problem just started happening again. its very rare right now but i know it will get worse. I cant keep buying plug wires any ideas whats messing them up? i now have 62,000 miles.

 

Okay now its happening all the time. Just upgraded to a 17% pulley so it really sucks having this problem with all this extra power. Could it be the coil pack? Should I buy an aftermarket. Im installing plugs hopefully tommorow, 1 step colder for the pulley.

 

I'm thinking it's the weak OEM bypass valve...

Your symptoms: Flat spots when slamming on the gas at low RPMs. Sounds like something a Detroit Tuned Bypass Valve can fix.

 

MrCooperS is correct. Stop throwing parts at it and remove the bypass valve. Check to make sure it is closing all the way and that the spring is functioning correctly on it.

Also yes you should put colder plugs in with your pulley. I don't think this will fix your current problem but I recommend it for longevity of the engine.

 

Plugs are going in tonight. ive check the valve and it seems good, boost gauge is showing nice readings also. I thought it could be that at first but once i swapped the wires and it went away, i knew it had to be either the coil pack or somthing more involved. Would anyone agree on the coil pack? When do they start to go.

 

Ok i have a MSD coil pack, wires and new plugs now. I ziptied the bypass valve closed and still felt a hesitation. Should i just go for it and by the detroit tuned bypass valve? Or could it be somthing else.

 

Where and how much were your wires? I have the Cobalt wires from MossMini and am experiencing something similar to your previous situation. My 03S is hesitant at 3krpm/70mph. Only at this speed and rpm though. Anything higher or lower and I am fine. Maybe if I revert to stock plugs, it would go away.

 

I dont remember the price but it was under $50 i think. That was for the stock ones. Check your hose running from the manifold to the fuel line, might have comne off, thats what hapened to me the second time and it had the same effect. This is the line that most people add a boost gauge too so look up a how too, to find it.