idle issue

[SACKO7]

I have a 1984 944, and it does not want to idle properly. It is manual and the motor performs well, but when I come to a stop sign or light it stops running. When it does idle it sounds like it is cammy or surging and eventually cuts out. Any ideas would be appreciated as people are now pointing and laughing

[M. Murphy]

Any recent work done on the engine? I experienced something very similar last year after a large vacuum line had slipped off its nipple under the intake manifold. Big vacuum leak!

[mytrplseven]

If you haven't already done so, I'd recommend spending a few bucks on the Lindsey silicone vacuum hose replacement kit. Also, the J boot has a history of becoming brittle or worn around the vacuum line fittings and should be inspected and replaced if necessary. Have you noticed a difference in fuel economy? It's possible you might have a plugged or failing fuel injector. Witch Hunter in Duval, Washington will rebuild your injectors for $100 and they're fast and well regarded.

[Fast Freddy 944]

You might consider taking it to a qualified mechanic, it may cost some clams, but peace of mind and nice sunday cruise will be the outcome.

[Project560]

People shouldn't be laughing at you and your 944. Everyone should pitch in ideas to make sure it doesn't happen again.

I am working on an 84 too and there could be a number of things causing a problem. If the vacuum lines are good, my guess is the Throttle Position Switch. It tells the DME controller when the throttle is closed (idle). The switch may need to be adjusted to close when the throttle is closed or the switch contacts may be the problem. Mine was full of oil from a bad air oil separator. The following link indicates how to test it. Throttle Position Switch - Information, Troubleshooting, Replacement, and Adjustment

Alternatively, Clark's has some good trouble shooting tips that might be helpful:
Engine Starting and Running Troubleshooter
OR Troubleshooting - Engine

If you figure it out, let us know what you did to fix it.

[guru944]

Recommend checking these:

Vacuume Gauge
Puel pressure Regulator
TPS
AFM
O2 sensor

Later...

[M. Murphy]

So, what's the latest?

[John_AZ]

Good advice from mytrplseven.
When 777 had the issue, and spent many hours and dollars-----it came down to the Porsche Motronic DME ECU.

Shop for a "good" used or send to Specialized ECU Repair, Replacement, & Testing - Restore or Exchange your Electronic Control Unit (ECU).

GL
J_AZ