FiveElements

My car had similar problems. Temp Sensor #2 had a bad wire a the connector bend that was intermittently loose. I cut the entire connector off and re-soldered a new one on. Everything is perfect now. $9 for a connector on eBay.

http://www.ebay.com/itm/HANDY-PACK-H...9828e5&vxp=mtr

dr bob

All those hoses in Post 14 above are suspect, along with the hoses that attach to the cam cover vents. They fill with oil and rot/split/fail. If they are original, they are overdue for replacement. Any failure means unmetered air is going to the intake, causing a lean condition that the LH can't compensate for when everything is cold.

Plugs: Put the resistor plugs in. The Porsche wires are not resistor, but the ends are. Correct resistance determines the firing voltage in a way that's somewhat counterintuitive. The coil charges, building a magnetic field inside. The initial collapse of the primary field induces a much higher voltage in the secondary winding. As that secondary field builds, the point on the curve at which the spark happens is a function of when the voltage at the plug is high enough to bridge the plug gap. The resistor delays the firing to a point higher on the coil charge curve. Once the plug fires, the resistance in the plug and wire end is moot.

alabbasi

Thanks, I picked up the connector today and will solder it on in place of the original. I may also pick up the sensor as it's not an expensive part.

I don't think that there are vacuum leaks as I went over the motor slowly with a propane torch and did not get a reaction from the engine. If the sending unit and connector fail, then I'll put it on my smoke machine and try to find the leak. That will be for next weekend.

alabbasi

Quick update. Today, I replaced the temp sensor itself, the wiring with a new plug and also the oxygen sensor. Unfortunately, this did not solve the problem and the car still runs very poorly.

MainePorsche

You've dealt with many of the usual suspects for bad idle that are easily accessible. Sounds like it's ISV time.

alabbasi

Forgive my ignorance, but what is ISV?

MainePorsche

Idle Stabilization Valve or ICV Idle Control Valve.
You can do a temporizing measure. You can spray some WD 40 to loosen up the door, but if it is that gunked up, you'd want to get a new one. I consider it a wear item. Best way to get the spray to where you want it to go is to remove the MAS and spray forward into the port in the driver's side of the MAS housing. Get you spray can tube as far forward toward the ISV as you can when you spray. Don't overdo it with the lubricant. Let it sit for a bit while you button things back up. Restart and see what you have. Do you have any idea when it was last replaced ? If you don't know, order one from Roger.

alabbasi

Thanks, willl give it a go. I'll also replace the fuel filter again and put a fuel pressure gauge on the rail to see what the readings are. More to come next week.

Thanks again.