Attachment 10106Hey all, so my 02 gtp started laggin out or sputtering while in full boost a few months ago. It runs perfect besides that. If I let off the throttle slightly when it starts to "miss" it is fine, I just cant lay in to it fully. Last week it threw a code P0420.. lol... which is numerous possibilities. I have aftermarket exhaust, which is how i bought the car a year ago. I have since replaced the oxygen sensor , but it didnt quite thread in properly to the new exhaust, probably need to clean the threads from slight rust perhaps? I do have a small coolant leak visible right on the gasket on intake a half inch from the injector port. There has been condensation on the oil filler snorkel every time I take the cap off, and occasionally , some slight yellow sludge which im assuming is a wee coolant leak from that intake manifold into the oil. Which could explain the code.
bla bla bla, anyways my question is what to do for this lag and power hiccup at full throttle? I will fix my oxy sensor and thread it in to full depth and do more inspections but thought i would throw this one on the forum for help.
thanks all.
Notchy.