Greetings gentlemen and experts. (both one in the same, right??)
I am having a VERY hard time with this car. I've almost got it running perfect but there's a few little things still buggin' me on it. I've done multiple searches on the subject and have found a few ideas and tried them. Short of replacing the fuel pump, I've done everything. What I need to know now is if I should go ahead and do it, or try something else before continuing.
It's a 1996 Contour GL. Zetec/Auto
Here's what's been done. (every one of the below improved performance....)
Replaced all fluids. (engine, atx, ps, brakes, etc.)
Replaced bad battery. (Fixed sluggish electrical, spark knock)
New Plugs, wires. (motorcraft) (made engine run)
all hoses replaced, temp sensors, flushed all cooling.
Replaced water pump.
Replaced all timing. (belt, pulleys, tensioner) (smoothed out engine, earlier belt was chewed, bad pullies.
Replaced serpentine belt, tensioner, idler. (old)
Sent out injectors for cleaning, balancing. (no leaks)
Replaced fuel pressure regulator (tiny tiny tiny leak...)
Air filter. (black)
Cleaned Maf / all induction. (again, black)
New TPS sensor. (fixed initial off-idle rev)
NEw PCV valve, hoses, all associated rubber..... (vacuum leak)
New DPFE sensor, EGR solenoid. Cleaned EGR valve. (VERY rough idle, sluggish power)
New IAC. (slight improvement)
New upstream O2 sensor (completed catalyst monitor, now runs closed loop. MPG improved by 4)
Checked Fuel pump pickup. cleaned. Nothing obvious. Checked electrical connection, OK. Pump voltage OK.
Car runs much better now. HOWEVER, still idles up/down, hesitates sometimes at low rpm (after idling a lot) and exhibits vibration when in gear. The vibration isn't there when you stop though. It comes on gradually, while idling. At first I thought injector leak, but I've checked that too and nothing. checked Ignition module resistance and appears to be in spec still. Plugs look normal too...???!!
The specific question I'd like answered is if anyone here knows the correct fuel pressure, with engine running at idle. According to the Ford CD, it's supposed to be between 35-45 psi running, 35-45 off. According to Haynes, it's supposed to be 38-42??!! I'm getting a consistent 29-30 psi running idle-4500 rpm. 39-40 with regulator vacuum disconnected. Initial priming before start is 20 psi / 30 psi / 36 psi. Highest possible prime is 36 psi, no higher...
Sorry for the stupid-long post. But I've had very little sleep. Any suggestions are GREATLY appreciated.