i've upgraded my '03 with s1, denso irridiums and wires, mopar bov and k&n cai. on the hwy i notice some stutter when i floor the gas at 65 mph in 5th gear. i've checked the usual culprits ie. plugs and wires as well as bov. everything checks out fine (gap o.k., wires tight and bov not leaking). the boost gauge does not fluctuate when the stutter occurs. would a wastegate upgrade help? my car's a daily driver and i do not intend on taking it to the track. however, stutter included, i would like to add some mods that would compliment my current upgrades. excuse the noob inquiry, i am a backyard mechanic with minimal turbo experience!

 

Try swapping out your plugs for some NGK 4306s gapped at .045 and some regular plug wires. That's generally a good place to start your diagnosis.

 

Thanks BigMac. I'll give it a try. Do you think the Denso's and wires are to much for the other mods I've installed and hurt the performance? Would a AGP or S2 wastegate help?

 

an agp or s2 wga would be most beneficial if you had a mbc/ebc on it as well. it will increase boost levels, but isn't going to stop a studder.

i agree that it definetly sounds like plugs and wires. if you want a set of denso's the ITL16's would be the plugs of choice for you. they're a stock replacement, but much better functioning. get those with a set of msd wires and you should be good to go. the ngk coppers are also a very good plug for a lightly modded car, and are much cheaper.

 

Thanks PSI. I currently have those Denso's and 9mm wires installed on my car. I'm going to swap them out and see if the stutter goes away.