I just picked up a 95 z28 for cheap! When I first drive it when its cold the car runs fine for like 5 minutes. Once it gets hot then the car runs like absolute garbage. pops and has no power at all. Takes like 4 minutes to get to 60. The engine has been completely built. What do you guys think the problem is?

THANKS!!

 

Gotta list the mods you know have been done to the car. Several things happen once the car warm up.

 

Need more info on the car. Mods?

Sounds like a closed loop problem, any codes or check engine lights?

I had a similar problem when I had an o2 fail, but if you can scan it and see what the sensors are doing thats a much better way to know for sure whats the issue. Could be a large # of things.

 

95 z28 mods are

block bored 30 over
forged steel crank 4340
forged flat top/dihed pistons 4340
6.0 in rod
comp cam roller lifters
hardened pushrods
gm 847 hydraulic roller cam
ported polished intake
ported polished heads 3 angle valve job
egr delete
bbk headers
off road y pipe
moroso cold air intake
flowmaster catback exhaust
under drive pully
1.5.1.6 roller rockers

That's what I know of

 

Any codes being thrown or check engine lights?

 

its def a closed loop issue.......O2's, ECT plugged in?

 

I am car retarded so im not sure lol

 

If you unplug your MAF you can keep the car in open loop. If the car stays driveable after warming up then it's likely a fueling issue with an O2 sensor, MAF, or some other component that alters the A/F ratio. Check all of your sensor wires and make sure everything is plugged in, no wires are burnt, etc.

Are there any service engine codes? (Keep in mind that unplugging the MAF will trigger a code) If it's not throwing any then the only way to really tell what's going on is to datalog the car and look for abnormal readings.