My 1989 Will crank for 5 or 10 seconds before starting when cold. Warm start is fine. It also idles rough when at operating temp. I've changed spark plugs, cap/rotor, wires and faulty fuel pressure regulator. I've adjusted the minimum air set per the Killebrew bible.
I've checked for vacuum leaks and have found none.
Fuel pressure is 44 lbs when the key is turned and drops to approximately 10lbs within 10 minutes. No signs of a fuel leak. Checked injectors for resistance and leaking. All good.
Can anyone think of something else to check?

 

I'm no expert, but I'd pull the vac line off the FP regulator and look for fuel. If any is present, replace it. They fail reasonably often, so it's worth a look.

 

Do you hear the pump prime when ign turned on ?? Maybe pump relay problem.
Any codes ??
Any fouled plugs ??
TPS set correctly ??

 

Know that mine was a hard start from the Factory - new injectors (a cheapo set of Accels) cured it - that was about 5 or 6 years ago, so I spent 10 to 11 years figuring it out. That included running all sorts of tests which essentially proved nothing other than that fuel was being delivered as promised.

Your rough running may or may not be related. Capturing data with a scanner might at least rule out or point you to a particular sensor - like the Engine Coolant Temp Sensor - which, if it's reporting a hotter than actual temp, could give you a hard start and a rough idle because the ECM uses that signal in place of a choke. On a cold engine, a scan should show about the same temp as the outside air temp and it should also be close to the Manifold Air Temp signal.

You could also try to isolate the roughness to a single cylinder. Cut some 1/4 inch vacuum hose into 1 to 2 inch lengths and insert a piece between each spark plug wire and the distributor tower. Disconnect the IAC harness so that it doesn't compensate for the idle drop (reset when you hook it back up by depressing the accelerator slightly and starting it - let it run for 10 seconds, then off for 5 seconds). With a tach or scanner in hand, touch each piece of vacuum hose with a grounded test light while it's running to kill the cylinder. Note the rpm drop - all cylinders should have the same drop (or be really close). Pay particular attention to #7 since that is where allmost all of the '89's have head gasket problems. In fact I'd pull that plug and check it for rust on the threads and see how it's electrode compares to a couple of the others. Any differences and you should check compression; run a leakdown test.

 

The fuel reg was blowing raw gas so I replaced the diaphram. Problem still exists. No codes are stored, all plugs look clean. I've checked the TPS. It's at .55v

 

Sounds like you have leaky injectors or a bad check valve in the fuel pump...pressure dropping to 10# in ten minutes is to far..to fast, kinda leaning toward the FP because it starts fine when warm. I eliminated the FP regulator as a possible culprit because you said you recently replaced it.

 

This is a little faster than normal for the fuel pressure to drop. You say you have checked the plugs and they are all clean. None were wet with gas correct? You can take the gas lid assembly and rubber boot off and pinch off the return line as soon as the key is turned "on" and pressure has built in the fuel rail. Watch the fuel pressure guage and see if it still drops as fast. Then do the same and pinch off the fuel feed line and see what the pressure does. The injectors should ohm around 16 ohms each.