1990 Jetta GL multiple problems

[fkm3]

I have a '90 Jetta GL 1.8L Digifant II (manufacture date 8-89) with multiple problems. Engine is hard to start hot or cold. Must have accelerator on the floor for it to start. After it finally starts the idle will sometimes run up to about 2000 rpm. I can tap the idle stabilizer with my hand and the idle will return to normal. After driving a short distance and coming to a stop sign, the idle will sometimes be back up to 1500-2000 rpm and sometimes surge. I can tap the idle stabilizer again and it will come back down to normal. I have checked the air flow sensor as described in the book and it tests bad when the flapper is moved and while monitoring the ohm meter. It sounds as though I may need to replace the idle stabilizer and the air flow sensor. I also checked the fuel pressure. At idle, 40psi; remove vacuum from fuel pressure regulator, 44psi. Turn the engine off and the fuel pressure falls to well under 29psi in about 2-3 minutes, spec is 29psi minimum in 10 minutes. Next I pinched off the fuel return hose at the pressure regulator and found no difference in the fuel pressure decrease. Next I pinched off the fuel inlet to the fuel rail and the pressure drop was slowed somewhat but still out of specs. Possible fuel injector or o-ring leak?? The O2 sensor was replaced a couple of years ago for a stalling problem after the engine warmed up. I do have a couple of small exhausts leaks well after the O2 sensor so I don't think they should be causing any of my problems.

I hope someone can help.

[fkm3]

Sorry that I have so many problems that no one could help. I followed the book on the fuel pressure concerns six months ago and the FUEL PRESSURE REGULATOR checked ok. I assume the diaphram inside was cracked allowing fuel into the vacuum system intermittently. It finally got bad enough that the fuel rotted out some vacuum lines. Regulator was replaced along with the vacuum lines and engine is running much better. I was convinced it was electrical/electronic, so all grounds were cleaned and I checked the ecm power and grounds and they were all good.

[trev0006]

I think its time for a trade-in