robby73z28

i have 383 i have a mis bout 4000rpm now i replaced opti wires plugs coolant temp censor had tune on computer dne cant figure it out plus it will run awsum for 15mins after that blows thick black smoke and wont idle wat the fu@k can this be sumbdy must have had this problem befor any advise would be great thanksssss!!!!!!!!!!!!!!!!!

Imnotfast

iTrader: (1)

sounds like grounded O2 wires. Normaly near the pass side frame rail. Headers get really really close there

smoknta

Yeah sounds like it has issues once it hits closed loop. Look for a problem in the O2's or things that can cause false readings in the O2s. What exhaust are you running? Are you running headers? Do you have heated O2's? Do you have an exhaust leak before the O2's? What do the O2 readings look like when datalogging?

Formula350

iTrader: (3)

I third the O2. After the 15mins it goes into open loop and reads the sensors, when it hits the O2s. WHAM, the nastiness occurs.

I got my fingers crossed for you!

Imnotfast

iTrader: (1)

Did you ever find the problem?

robby73z28

dnt kno i looked had a hole in my exhaust above the o2 gonna fix it tmrow

Imnotfast

iTrader: (1)

if its a hole near the O2 then that is your problem. It will suck in fresh air and think it lean.