Wolfie660

Hi guys, hope you can shed some light on a issue I have with my 92 SC4
I got the car a last month form a "enthusiast" and at first she was ok, however now she has a hot running problem that is really annoying!
when the car is cold she run great, power everywhere, but when she gets hot, its like she is missfiring, really sluggish but seems to clear after 4500rpm and the idle is crappy with a slight missfire which can be felt as vibration thought he doors when open and a "popping" noise from the exhaust, sounds like a dead clylinder.
BUT!!
if i disconnect the AFS, she run sooo much better, if not a bit on the rough side.
So far i have replaced the Dizzy caps, rotor arms and sparkplugs.
I have also replaced the AFS with a good used one.
checked the timing.
have checked the resistance of the leads when hot and cold, which are within specs.
the IACV has been also checked and is fine.
the only mod the car has (on the performance side) is a decat system, which is making me think O2 sensors are playing up perhaps?
what do the masses think?

GS4_Fiend

iTrader: (22)

Make sure those o2 sensors are working. The ones before the cat. I would look at that first. Your car got a severe rich misfire thats why its back firing to the exhaust

ihiryu

iTrader: (7)

Do a search on the coolant temp sensor. They go bad after time, and it'll think the car is running super hot so it retards timing to make up for it.