Engine Performance problem
1995 Ford Taurus 6 cyl Front Wheel Drive Automatic 150000 miles
1995 Ford Taurus SHO 3.2L Automatic.
So I acquired this car recently from a relative and found it often either runs rough or wants to stall out all the time. Apparently my relative had this problem with the car as well. I'm pretty frustrated and tired of throwing money at it at this point, and would REALLY appreciate some advice!
What I've done so far:
1) New fuel filter.
2) Tested fuel pressure, it's OK.
3) New air filter.
4) New Throttle position sensor (because it was such a cheap and easy thing to try)
5) New EGR Pressure Switch (because it threw an engine trouble code, code gone after replacement).
6) Checked EGR system, seems to be working correctly.
7) New O2 sensors (because it threw an engine trouble code, code gone after replacement).
8) New Ignition Control Module (because engine was throwing codes 215, 216, and 217).
9) Checked all ignition system connectors for corrosion, none was noted.
Now after all that, the engine continues to throw codes 215, 216, and 217. The plugs, wires, and coilpack were replaced not long ago by my relative in an attempt to solve this same problem. I could try throwing a new coilpack at it, but I have a suspicion that's not the problem. Today I noticed that the engine is PARTICULARLY prone to the running rough and attempting to stall when the transmission is in Drive, 1, or 2. This doesn't seem to happen when it's in Park, Reverse, or Neutral.
Some other things to note:
1) The engine usually seems to run fine when it's idling in park in my driveway. However it does sometimes start to run rough and I have to keep the RPMs around 2000RPM for several minutes to keep it from stalling.
2) The car has sat for around a year without being used. I suspect the gas is stale, and I'm trying to run it out of the tank since I can't seem to be able to siphon it out. But since the car usually runs fine at idle, I'm not sure if this is even an issue.
3) ABS light is on, but I'm not concerned about the ABS system.
So my questions are:
1) What, if anything, should I try to do about the codes for the ignition: 215, 216, 217? Should I try a new coilpack? The only other ignition components left are the Crankshaft Position Sensor and Camshaft Position Sensor. I find it strange the car will usually run fine but is throwing these codes.
2) What could cause the car to be more prone to stalling/running rough when the transmission is in Drive?
Some updates: I ran the old gas out of the tank, and put 5 gallons of fresh gas in. This didn't seem to make any difference.
I got the Haynes repair book for the '86-'95 taurus, but the book doesn't cover the ignition system used in the SHO. I found the Ford Windstar from the same era uses a very similar ignition system.
I tested my coilpack based on the specs in the Windstar manual. The secondary resistance of my unit seemed out of spec, so I got a new coilpack from Autozone and the new one matched the spec. I replaced the coilpack and the engine still ran like complete crap for several minutes, but then moderately improved after it warmed up. I used the dielectric grease on the terminals.
At the time the engine was running fair, it still seemed to miss every so often. No failure codes are returned now, so I guess that's at least progress! Where do I go from here?