bmohr

I have a very strange issue that is noticeable on smooth roads at low gears 2 or 3 at steady speed. It feels like a push pulling type of gyration. Not quite a studder, not a hesitation, not a jutter or bucking. It's like all of these but mild. Thats the best way I can describe it. I thought maybe this could be a symptom of a failing ignition coil but when I remove each of the ignition controllers one at a time the car starts and runs without a hiccup. So I have to assume both coils, caps and rotors are operational yes? New wires and plugs put in just a short bit ago..thought I'd add that. Now, at all other times the car runs well. I think I need to clean out my isv but otherwise It runs well. Anyone else have a similar issue? It's so vague in description I'm having a hard time finding another account of this type of symptom.

BHCfarkas

I believe I know and have this same sensation you're describing at speeds around 35-45. It's as if the car surges slightly, despite the throttle position being constant.

I haven't looked into it too much, but in the past with other cars, primarily VWs and Toyotas with similar flapper-type induction meters(AFM), it's indicative that they either need cleaned or replaced. The ISV could certainly be the culprit as well as neither my AFM or ISV have been cleaned while the car has been in my posession.

Indycam

..

BHCfarkas

Indy, no... only when there's a load on the motor in my case.

HiWind

azander

I have that too, holding constant speed up to 3000rpm type thing. It's like it's pulsing. I just had my transmission swapped from tiptronic. It's more prominent now due to the gearing. Basically every sensor was checked or replaced during 'debugging.' New coils, etc. How it always was. Guessing it's the nature of the beast... she wants to go.

bmohr

sht guys, thanks for chipping in, glad I'm not the only one with this vague issue. You guys both described it better than me though. So in my case I haven't tried putting it in neutral while coasting but I believe I've only noticed it under load at that 3-5k rpm range just as described. I'll give it a try today and see. I'll try cleaning the isv first and see how that works.

bmohr

cleaned ISV, tried coasting in neutral, no effect. Still has that pulling effect just under 3k rpms (2800-2900) in 2nd and 3rd gear. Could it be related to the resonance flap maybe? I'll troubleshoot some more and report back. Only other odd thing I could note is having to re enter my radio code from a cold start.

Navaros911

Dirty injectors?

Having them cleaned made the car run much smoother and did away with the mild stutter on stable load.

lateforlunch

bmohr - I see you have MAF listed in your sig, does that mean your stock flapper box air flow meter is gone now? are you running a 993 hot wire air mass?

Im asking because I have seen and fixed this problem on stock flapper box air flow meter equipped cars before.
If you have a different setup my advice will not apply.

jevvy964

Once its up to temp and doing its funny thing pull over and pull the ISV plug. If the engine is warm enough it should idle ok with a bit of help but see if it has the same surge feeling when on constant throttle.

BHCfarkas

Thank you for the suggestion, I'm going to give this a try when the weather looks up.