Another question regarding my son's 87 944S. The idle is spotty at best. Saturday it wouldn't idle and died if I let off the gas. After about the third time running it for a few minutes, I backed it up into its parking space and it just started idling at around 750-800RPM like it was a kitten.

We bought the car last year not running. The PO said it was running fine and he drove to the doctor one day, came out, and it wouldn't start. Apparently it hadn't run for about 15 years when he bought it, and he did a decent list of things to it to get it running again. But not the timing belt or water pump, which would be (and was) my first thing to do.

We've done a lot of stuff to it to get it going, such as:
Timing belt, water pump, timing chain tensioner pads
New timing belt tensioner
New belts
New coolant hoses & reservoir
Newly rebuilt AFM
New plugs & wires
Rebuilt Bosch injectors
Fuel filters (in tank and in line)
Fuel pump
Rebuilt the notorious 3 prong male & female connectors for speed reference and Hall sending unit - the males were crumbled to dust
New Idle control valve
New vacuum hoses with venturi delete
New O2 sensor

It desperately needs a new exhaust, but the lack of idle and feeling like it is starving for gas at higher RPM's is getting old.

With as much as we've done, it has to be something simple we've missed. We double checked all electrical and vacuum connections.

Any ideas from those more experienced with these cars than me?

Thanks in advance!

 

If I understand your question the car is having trouble when cold? After it warms up it idles ok? When you checked the electrical connections how did you do that? Did you check resistance/voltage at the DME plug or did you just check to make sure it was all plugged in? You need to check at the DME plug or CUT all the boots off of all the connectors. The wire insulation under the boots degrade and the wires short out. When the DME temp sensor connector shorts out under the boot the car will be hard to start and will run rough until it warms up. Most problems on these cars are due to faulty electronics and wiring. Another possibility is the coil driver in the DME. Could have a bad solder joint that barely connects when cold but works when hot. I would pull DME and look for bad solder joints, especially the coil driver.