94 Z28 Hard to start when warm
 

I have a 94 Z28 that starts fine when cold or after sitting for a long period. Once the car warms up an you crank it the engine acts like its severly out of time. It kicks back on the starter and sputters and rarely starts. Let it sit for a couple hours and it spins over fine and starts right up. Is there an adjustment on the timing on these motors? This is my first one and need to get this fixed. Any ideas? I scanned the car today and it throws codes 26,27,84,77.

Re: 94 Z28 Hard to start when warm
 

26- Evaporative Emission (EVAP) Canister Purge Solenoid Valve Circuit
27- Exhaust Gas Recirculation (EGR) Vacuum Control Signal Solenoid Valve Circuit
77- Cooling Fan Relay Control Circuit
84- Automatic Transmission 3-2 Control Circuit/Skip Shift Solenoid Circuit (Manual Transmission Only)

Doesn't look good. Since the codes don't really help, here's some ideas for things to check:

Ignition system (plugs, wires, coil)
Fuel delivery (fuel pressure)
Vacuum leakes (Intake manifold and vacuum lines)

Parts that could be bad:

Fuel pressure regulator, fuel injector, optispark, coil, ignition control module to name some of the more likely culprits.

Re: 94 Z28 Hard to start when warm
 

what he said

Re: 94 Z28 Hard to start when warm
 

Thanks for the reply, here's an update. I changed the #2 and the #3 fan relays and now I get no SES and the car actually runs better. Could the trouble codes be related to those 2 relays. Now I get a light on the dash that says skip shift when I'm in 1st gear, never seen that before and I can't go into 2nd. I cheked the fuel pressure and it is fine both primed not running and running.