redtop studdering under boost once warm

[scote2583]

car is a 93 240sx with a redtop sr 20 in it, before i parked it for the winter it was showing the problem..... when i first start and drive the car for the first 5 mins its fine, runs like a champ but it seems that once it gets warmed up it falls flat on its face when i get on it, it studders and backfires, i dont really wanna replace stuff that i dont have to so looking for ideas here first. my original thought is a bad o2 sensor, please help

[jacobs13]

Im pretty sure its your timing. Warm up the car and then set your timing with the proper procedures

[scote2583]

the car is running on stock ecu with no extra tuning , was running about 13lbs of boost, bought car in august ran great up until October, the reason I'm thinking o2 is that the o2 wire looks a little melted from contacting the manifold, it doesn't look melted all the way through though so not really sure

[scote2583]

what would have caused the timing to go off? and where do I find the proper procedures

[Sileighty_85]

check ECU for Codes almost sounds like the Coolant Temp Sensor

[JayZeeSILVIA]

could be coolant temp or o2 sensor. the ecu ignores the o2 sensor until it warms up. replace the wire on the o2 sensor and see if that helps. also if i remember correctly you should have between 0-5v on the coolant sensor depending on measured temp.

[scote2583]

weather got nice out and roads were clear so I took the car out an re-evaluated my problem and figured out that it does it right away sometimes when I go WO throttle, my friend who was in the car with me said it sounds exactly like his did when the plugs were toast, so ordered some new plugs and hoping that it is just a simple stupid problem

[spartanmisfit]

have you checked for boost leaks? Have you checked for vacuum leaks?

[scote2583]

have you checked for boost leaks? Have you checked for vacuum leaks?

yeah, when problem first started that was first check, waiting for my NGK's to get here hoping thats the problem