scb8mp

I have a 1981SC Targa, that just recently underwent a full rebuild including a new clutch. This is my first porsche, and had the rebuild done shortly after buying it. The engine starts right up, it does idle a little bit rough for the first minute or so when cold. After warming up, it idles smoothly around 950RPM. In neutral under no load, the engine revs smoothly. However, when driving it the acceleration is very sluggish, and trying to accelerate in 2nd or 3rd gear causes the engine to struggle and start to shudder fairly significantly. Once up to speed and at a higher RPM, the shudder isn't present.

So far, I've changed the O2 sensor, didn't really make any difference. I'm suspecting dirty/bad fuel injectors, so I've tried running some injector cleaner through the tank with minimal effect. I haven't put many miles on it though, since the car is barely drivable with how poor the acceleration is. How often do injectors completely go bad? What's next to troubleshoot? Mixture? Vacuum leaks?

theiceman

I rebuilt my own engine. I had cis sitting in garage for 2 years and ran like a scalded cat after. I would talk to engine builder
Sounds like cam or ignition timing may be off.
Also check vacuum advance

Catorce

Define "rebuild". Also, is this a CIS car? Was the CIS system rebuilt? need to know more.