Problem Solved - guess what it was...
 

O.K. this problem that I have been chasing for the last 6 months or so is solved. If you are interested, let's play a game. You guess what it was and I tell you if you are warm or cold. The first person to guess the complete answer gets a $50 gift certificate to Pelican Parts.

Here are the clues:

Starts great hot or cold.
Runs good until warm then there is hesitation at constant speed.
Runs great above 5800 rpm if hot or cold.

Big clue: previous owner only half way fixed the problem.

Here are the things I tried to fix it, but they didn't work:
Replaced fuel filter.
Replaced fuel pump with internal check valve.
Sprayed carb. cleaner to check for vacuum leaks - NO LEAKS.
Set timing.
Checked electrical distributor cap - fine.
Checked fuel distributor for a fouled plunger, but failed in my efforts, but that wasn't the problem.
I could give the answer here, but if you are interested, let's have some fun.

Bottom line: problem solved and I am :)

The answer is too easy! You gave it away in your signature..
It's a Targa. They ALL do that. Apologies...I really don't have a clue. But how many times have we all heard those four words from a dealership service manager? (An oxymoron in it's own right.."service manager") THEY ALL DO THAT???? Like by saying this, "THAT" is suddenly okay? :)

fix
 

temp sensor or flywheel position sensor...that's my guess.

Ok..

It's gotta be related to the injectors, right? Needless to say, they'd get new seals if you replaced them. Possibly the Beru connectors/plug extensions also. They were a major fault on my 2.7, causing it to run on 4 glorious cylinders!

Adam: injector - cold
avi8: flywheel positioner - cold. Temp sensor - cold.
72s: WTF?

I'll be checking reply's tonight and tomorrow morning, but I have a race all day tomorrow. Then back at it again Sunday night and the rest of the week.

Is this fun?

razorracer, i don't have a clue, but i'm just glad it's fixed! congrats!

Thank you Adam. This is a high moment in my P-car life.

Razor, I'm pleased it fixed. This has been bugging me too being an SC man.

Was it due to the charcole filter being removed and a leak getting into the airbox causing a lean mixture?

Bill '79SC

Thanks surfer dog. My board has been neglected in my P-car efforts. Not much wave here in Houston.

Sorry to say that the charcol filter is cold.

Man, I'd love to try some down under waves.

Lets see how about the cdi connection or box, Kevin

Razor!
Time for mucho joy! I'm waiting to hear what it was....(obviously none of the things we suggested)

The excitement builds....:D

The vacuum advance unit on the distributer was bad.

Specifically the spring in the vacuum advance was allowing too much timing to early in the rpm range, once the engine reaches 5800 it's close to the point where total timing should be in effect and therefore the problem "goes away" since the engine needs that much advance at those rpms.

Possibility number 2 would be a no-functioning mechanical advance which wouldn't give the engine enough advance under load when the vacuum signal is weak and therefore the vacuum advance is barely functioning.

Razor --

The muffler bearings?

There's nothing like putting a stake through the heart of a tenacious automotive problem -- congrats!

- JP

WUR?

Bobby

joeycat: thanks for all of your help. You kept me going throught the rough times.
boom: you are very warm with #1 and I think you have answered the problem. It's not exactly what I was expecting for an answer, but you have the right idea. Can you please elaborate for us who are not a knowing as you?
Slacker: WTF? muffler bearings?
bob: WUR was a first check. Took the vacuum line off and expected the problem to go away, but it didn't. WUR: cold.

Ha you mean tha cat converter was pluged, Kevin

Kevin: cat converter was not plugged. Should have mentioned that as one of the things checked, but forgot about it.

Boom: you have the answer, but please elaborate on how you knew this. Many before you have tried, but you hit the nail on the head. I want to share my personal experience how I found it, but am waiting to hear more from you.

Razor -

A joke. I had no clue.

PO halfway fixed it?

JP

i believe boom has the answer also, as either the advance was rusted or the wire to the distributor was bad, if it is the answers it was booms, yo da man boom, :D , Kevin,,,, i think i am spending to much time on this bbs, i need to get a life and stop eating sleeping, thinking Porsches all day, well maybe not when I sleep,:rolleyes:

Fuel pump relay socket.