Ok, so my car has a real hard time starting only when warm. Ive replaced the Fuel Pressure Regulator with the Caspers AFPR, and I currently have it set to stock pressure. I put the fuel pressure guage on my fuel rail, and after I have the system pressurized (turning the key on and off a couple times to build max pressure in the rails, then turning the key off again) I notice that the fuel pressure slowly starts to drop. Usually 3lbs in like the first 2 mins. How do I tell exactly what injector is leaking fuel???

::Some additional info::
Car cranks and cranks for a long time before trying to start, and I have to hit the gas pedal to get it to catch. And once I do get it to catch, I have to keep pumping the pedal to keep it running, and the thing sounds like it's running underwater. Chugging, and a definite miss (not spark related {so don't say plugs or wires or fuel filter cause they are all new} ) I also notice a puf of smoke out the exhaust and sometimes smell gas, so I am assuming the thing is flooding out. But within 3 or 4 seconds, it blows it all out, and smooths out and runs normal, and drives as if nothing was wrong.

fuel pump could be going also


to check to see which fuel injector could be problematic, you need to take off the upper intake, and pull the fuel rail off of the lower by removing the 2 bolts that have it secured to the lower intake. you will want to keep everything attached (fuel lines, harness, etc.).

once you do that, you can place some small dixie cups (those small cups you see in peoples bathrooms) under the injectors and prime the system again and then watch for which injector is leaking.

if none are leaking, your probably looking at a crapped out fuel pump, or one that is on its way out.

oh, i almost forgot.....


the hard start could also be from a vac leak. make sure all hoses, clamps, fuel injector o rings are sealed properly.

however, a vac leak will not cause the pressure to fall off.


does it fall off totally or just those 3 psi after a couple mins?

It keeps falling off. And I'm pretty sure all the vac lines are in good shape. Hopefully I can give this a try this afternoon. Thanks for the info

if the pressure keeps falling off at the fuel rail, you have 1/2 of the issue pinpointed...


leaky injector(s) or dying fuel pump