I have a 93 Z28 that sat for a while. The guy who had it before me did the following:

New fuel pump
New Opti
New Ignition Coil
New Ignition Module
New MAP Sensor

The car took a crap after he had the tranny rebuild.

I replaced the fuel pressure regulator which was the one thing he didnt replace and this got the car running. The car was running pig rich at this point. It would fall on its face at slower speeds and act like it wanted to take off when id floor it. I replaced the spark plugs today, they all smelled like gas and were black ( a side note...I swapped out all the plugs from the top, it didnt seem as difficult as most make it out to be ). I have some new wires for it and 2 new O2 sensors. What else could I look out for as to what could cause it to run like this?


I did check the EGR by pressing it in while the car was warmed up..it would cause the car to stumble a bit while pressed. PCV valve seemed to be doing its thing too. It does seem to have an exhaust manifold leak...i bought the gaskets and im going to do those too.

 

Are you actually going to belive what the guy who sold you the car said? 80% of the time its b.s. verify some of them by taking a look.

 

Well from what I can tell the fuel pump isnt making any crazy noises and the other stuff seems to at least look pretty new. The plugs made a huge difference to where its idling correctly now.

 

Check if that Opti is new and if its a factory piece. It should be pretty easy to tell if it hasnt been driven much.. I would also get a fuel pressure guage on there to check whats going on with the pressure. At least you can rule out fuel then and look elswhere (ignition)

 

Change the fuel filter and clean the maf. I would change fluids and the air filter if not done yet. The O2's sensors could be bad. If you have a scanner that would really help.