Rough Idle and hot start issue 1975 with 993 conversion
 

I have a 1975 with a 993 engine. Wanted to ask you if anyonecould give me some advise on the following problems I am having:

1)On idle, the car is running with a bit of a misfire. However, once you press on the gas, full throttle, its runs excellent, seems like the power is greatest after 3000 rpm.

2)Also on cold starts (45 degrees and below), the engine starts, but stops right back up. I have to restart several times, keep gas pressed in order to keep it running, and its

3) Occasional on hots starts, the car hesitates. This is when I drive in traffic mostly. I changed the starter to a higher torque one, but did not help.

Basically, I have established the car is running very rich at all times (fumes). Is there anything I can do to improve the low, , speed city driving


The ECU is from the 993, no plug on it, I'm guessing its running on "open loop mode". Also no 02 sensors hooked up. The spark plugs are new. Any tips? What areas I can focus on? Thanks for your time?

Has it popped an error code?

Find and test the cht (cylinder head temp sensor ) on the front of the drivers side head. Its resistance changes with temp and functions like a choke to enrichen the fuel injection. If faulty it can cause the engine to run very rich (stinky rich) and makes hot starting especially difficult.