84 Carrera Hessitation / bucking

I'm in dire need of advice on a hessitation and bucking problem on my 911 Carrera. I've been through everything except the valve adjustment (could it be that simple?) The car starts rough, idles rough, hessitates and bucks between 1500-3000 RPM, but pulls like a freightrain above that. I installed a new O2 sensor, and that helped some, but it wasn't the problem. I torqued the intake manifold bolts and tested them for leaks, not the problem. New fuel, air filters, new plugs and the wires tested OK. What else is there? Please HELP! Oh, 118k miles on the original 3.2 burning no oil, reading abnormally high oil pressure.

Okay...my car read abnormally high oil pressure too. Like as soon as you turn on the car, it's all the way up (don't remember numbers offhand).
The sender unit is probably broken. They replaced mine when I had the tranny rebuilt.

Bucking...well, my car missed badly. I mean, it idled like a 66 chevy...no Porsche purr.
When I accelerated, it was strong.
So to summarize the problems before I had them fixed:
Very rough idle.
Popping (missing) in exhuast
Appeared to be intake leak, but wasn't

Turned out the be 3 bad injectors.

84 Carrera



[This message has been edited by Kurt B (edited 08-24-2000).]

Kurt may be right... see if any injector cleaner makes a difference. May also want to see if someone can do a power injector cleaning if the cleaner in a can doesn't work. Haven't seen any posts on power cleaning injectors, but that doesn't mean its not available. New injectors sound expensive (especially if its not the problem)
regards,
jlex.

Attempting to eliminate a double post.

[This message has been edited by stlrj (edited 08-25-2000).]

In addition to cleaning the injectors, I would seriously consider the possibility of a vacuum leak.

My 86 Carrera suffered the same symptoms due to a cracked breather hose (the one that goes from the top of the crankcase to the oil tank). With heat and time the normally supple rubber hose turned to a hard plastic like consistency at the top of the engine.

Even with that vacuum leak, it seemed to run amazingly strong above 3,000rpm as you mentioned,Mark. And since repairing the hose it seems to have lost some of that top end while eliminating the rough idle.

Hmmmm, did we just stumble on a simple, if not elegant, approach to increasing top end?

Joe


Sorry for the double post, but this computer thing keeps confounding me...Helllllp.


[This message has been edited by stlrj (edited 08-25-2000).]

[This message has been edited by stlrj (edited 08-25-2000).]

[This message has been edited by stlrj (edited 08-25-2000).]

I had a similar problem with my '85 Carrera. When I took it to a detail shop and asked for a steam clean treatment on my engine bay, they instead soaked the bay in degreaser then hit it with a high pressure wand for a few minutes. Jackasses. When I took it home it was bucking, missing, and otherwise behaving terribly at peak RPM. I went nuts checking plugs, distributor, etc. for water or damage...nothing. I finally gave up and took it to my mechanic. They found that part of the circuitboard in the air flow sensor box got fried. The last track on the board was for "wide open throttle" and was literally burned away. So the car didn't know what to do with my foot on the floor and just puked and bucked. $500 later, she was running like a champ again. Damn monkeys and their pressure cleaners.

I belive on 79 and newer cars they flush out the injection lines. Marque Mortors in Portland Oregon does this, they have some kind of machine that they hook up some where and flusn it out. Might be a thought.