Got a 96 z28. Only mods are ram air intake, headers, and programmer. Ive been noticing my car running a little rich for a couple of weeks now. However, I didn't realize how rich it was running. When I changed the oil I got a whiff of fuel on the bottom of the oil cap. What normally causes this? I was thinking a fuel injector might be stuck but if so is there a way to tell which one it could be? Or any other suggestions please.

 

I have the same prob, Mine is rich as heck, I just bought an autometer fuel pressure gauge to install, Im think my regulator is shot, since I checked the injectors, changed map, tps and mass sensors.....and new plugs..lol

 

First of all you should make sure there are no trouble codes, and that the engine is not misfiring and dumping raw fuel into the cylinders. Also check out the O2s and MAF.
You can check the fuel pressure with a gage and notice how fast it drops. If it goes down quickly it could be due to a leaky injector/s or a fuel pump problem. If the pressure holds then the injectors are not leaking. To actually see if an injector is leaking, the fuel rack and injectors must be removed from the intake manifold as a unit while still attached to the fuel lines. After that is done the FI system has to be pressurized. You can turn the key to the ON position for a few seconds and then OFF, repeat several times, and then leave it to ON. Better yet, provide 12 volts directly to the fuel pump test connector by the passenger wheel housing. Now you can observe all the injectors and see if any are dribbling fuel. Go to each injector and tap it sharply with a screw driver handle to make sure there are no hidden leaks. This is not fool proof, so if you have the ambition, remove all injectors and send them to a cleaning and test facility.

 

^^^ agree, check fuel pressure, check 02 sensors to see if they are fouled, check spark plugs to see if they are fouling, look for exhaust leak. may be a good idea to have the injectors cleaned and flow tested at an injector shop, doesnt cost much.