tkerrmd

Well Doc I think your story at the stop light really sums up what is happening to me. I have the car back now after the dealer extracted $1200 and corrected nothing. I also can "force" the car to stall as Dock has described.
What does anyone think of seeing if the programing can be reset to increase the idle rpms to say 1000. Mine currently seems to be slightly less than 800??

Sounds good Mike, see ya in Nov!! hopefully sooner?

markski

Tom,
do you have the original exhaust.... spend a couple of hours in the garage and put it on.... see what happens...
just an idea.
markski

Oak

could be a back pressure issue some engines are more sensitive than others but it seems like you would have noticed this from the begining. putting back an exhaust with cats would quickly find out if back pressure is the culprit.

kleinbbc2

I find back pressure not to be the problem.. You drove the car about 300miles with out a problem. The car did a 30min track time without a problem.. Why would back pressure wait so long to be a problem. I think the shop that works on your car has no idea what they are doing.. Take the car some
were else.. You always want a secound opion from a MD why not a secound opion from a shop..Also I would try Oaks idea just to see..

99firehawk

on other makes ive drilled a small hole in the throttle body to rasie the idle speed, im not sure how a pcar would react to that, I thik i have an old tbody at work maybe ill give it a shot for test purposes

Oak

tom, what about plugs and coil packs? did you have these checked or changed out? could possibly be fouled plugs. any cel lights?

Dock

Back pressure is a description of how restrictive the exhaust system is from the headers on back...it a measure of how hard it is for the engine to force the exhaust charge through the system and out the tail pipe. I believe that in an off-throttle situation, the turbos are the most restrictive piece of the exhaust back pressure puzzle. If so, then straight pipes would not be able to reduce the back pressure below that already established by the turbos.

Dock

I believe idle rpm (stock) is ~750. I personally wouldn't change it.

tkerrmd

Mark, Oak, good idea and the dealer offered to put on a new exhaust at their expense to see how things would good.
Dock, thanks for the info and input and I assume your physics answer is correct, and that's what I thought.
Well my buddy up there with the 964 KleinBBC is a great friend of mine and although has his own turbo problems, he is forced to live through mine also. Since what he said is true, he climbed under the car this weekend, and found two oxygen sensors very loose almost backed out!!
He tightened them and I am pleased to report, at least at this moment in time the car seems to run great!!!!!!! Yep, believe it or not, between the "tinkering" the dealer did, and then my friend finding the loose oxygen sensors, the car pulls again like the beast it was and I cant make it stall out any more.
Moral of the story and long story short there was no one answer, the combo of a bunch of things at the same time and the loose sensors did it.
Thanks all, especially Dock, Oak, Firehawk, and Klein!
Back in the sadde, 4 track days coming up, I'll let ya know!!!!!!!!!!

Oak

that is good news! it must feel good to be back in the saddle again! enjoy!

99firehawk

see fresh air hitting the o2 sensors .......

tkerrmd

thank you guys again, the fresh air and sensors dont mix!

drjoe

tk what software do you have and do you get a check engine light?....also do you "feel a difference with the cat removal?

joe

tkerrmd

Joe, I have REVO stage 2 software. It is written to run the car without the cats so no CEL. I had 100 cell cats and straight pipes before. car makes the same sound and turbos spool FAST! I love it.
pm me if you have any questions.

tom

mdrums

Tom, glad to hear the car is running awesome again! I can't believe the dealer did not check the sensors while they had it in for so long.
Hope to see you soon, Mike