Xxbistrumxx

Hey guys new to the site, hoping to get some help. I just bought a 95 Z28 Lt1 everything looks stock, clean car. When I bought the car the cat was clogged, so I cut the cat out. The car has a Rough idle, looks like someone has replaced the plugs and wires, I'm getting spark. Could it be the opti spark even tho I'm getting spark? It seems like if I unplug the cyl 1 injector plug there is no difference in idle which leads me to believe there is a problem with cylinder one. There is no service engine lights or anything. The car does crank a while before starting. Fuel pressure is good. Any thoughts would be great thanks guys

shoebox

Might want to actually check some plugs and also check for correct routing of the wires. Rough idle or misfires could have contributed to the demise of the cat.

Xxbistrumxx

Sorry I should clear up; I checked the plugs and wires which lead me to believe they had been changed, they look brand spankn new

Injuneer

Check for a leaking injector. Hook up a fuel pressure gauge to the Schrader valve, turn the key to run to prime the fuel pump, and note the pressure when the pump shuts off after 2 seconds - should be about 40 PSI. If the pressure drops rapidly after the pump shuts off, could be a leaking injector. And a rapid drop in pressure and a leaking injector will extend the cranking time. Does it start quicker if you put the accel pedal on the floor BEFORE turning the key to "START" and hold the pedal on the floor until the engine starts? That puts the PCM in "clear flood" mode.

Could also be a leaking fuel pressure regulator, leaking line or bad check valve in the fuel pump. If the pressure drops rapidly, pull the rails up with the injectors intact and pressure the system (do NOT turn the key to "START"). Look for drips from the injectors.

capncrunch

Good answer Fred!
Also, I think what Shoebox was saying is that IF they are new wires, they may not be going to the correct plug and distributor terminal. It may be mis-wired.
And yes xx, it can still be the opti, even if it has fire. So, don't rule it out yet, either.