Hesitation with cold motor
 

Can someone tell me why my 2005 997 hesitates during take off while the engine is cold. Keeps doing that until engine oil warms up yo around 200. Changed the spark plugs since car has 63K miles. Need to clean body throttle? Please help.

I had a similar issue. I changed the plugs and a faulty coil, it solved the problem. if you changed the plugs I would check the ignition coils next.

Did you change all the 6 coils or found the faulty one?

I changed just one, it was cracked.

Thanks. I need to check mines. Are the crack easy to identify? Cracks on plastic housing? How much to replace?

yes, fairly easy to spot. They are about $50 a piece (ballpark) I should have replaced them all last year. The coils are a know issue.

Thanks krysFly for your help. Great forum!

Guys, still having hesitation problem. New spark plugs and coils looked ok. What else should I check? Is this normal when engine is cold?

Is this a serious question? j/k When you say hesitates, do you mean a significant off idle stumble when cold, or just a noticeable power difference under acceleration? Are you overloading the engine when cold? Cars are engineered to run properly at operating temperature. No cold engine runs as well as when the engine is operating in the designed temperature range. Lots of factors could be related to poor performance. Stop guessing and take it to someone who can determine an issue if there is one.

No. This is not normal. My cars always run the same whether cold or warmed up. The difference is I never push the car too hard until it's properly warmed up.

Would suggest you clean the throttle body and MAF sensor if it has never been done. CRC makes a seperate spray on solution for both. Auto Zone has 'em. Just did mine after noticing build up inside throttle body. If it's there it's on your MAF.

Thanks danversteve and dadio. I never push my car when cold. That is a given. Also, cleaning the MAF was my next item to check. It seems that it is a very common item to do. Is cleaning the body throttle also very common? What should be the frequency on both MAF and body throttle?

I have a BMC filter in my car which may have contributed to the greasy stuff coating the throttle body near and on both sides of the butterfly. I'd check it for any build up at least at each filter change and make your decision based on what you find. Interior surfaces should be clean and shiny, if not, it's needs cleaning. Best method is to remove it from the engine to clean it as cleaner is not plastic or paint friendly.

I've never had to do it after three Porsches. Before taking anything off and cleaning it without a known need, I would run a bottle of SeaFoam through the system and see if that helps. It usually cleans things needed cleaning pretty well.

Agree with this no-touch approach. But since I don't think it will be heeded, my only suggestion is make sure you explore and clean during the week so you can run to the dealer and get new parts when you break something. Seriously, physically messing with the MAF is a disaster waiting to happen. OP really needs to better define what seems to be the issue when cold, anything from noises to power irregularities. I'm assuming everything runs normal when warm. That in itself has me thinking there probably isn't an issue. With that, I think I'm done.

I just cleaned the MAF sensor and the car feels better, but not completely fixed. I did not clean the body throttle. It looked like it might need some cleaning. I might do that next weekend. Let me describe the problem once again. The issue is more pronounced when the engine is cold. I feel it the most when taking off from dead stop and when I take off slowly (1500-2000 RPM). It feels like the engine wants to die and then it takes off. As the engine warms up,the problem is less noticeable, but still there. I hopes this clarifies the problem. All suggestions are greatly appreciated.

My car was doing the same thing, hot or cold, from a stop. Had to feather the throttle to avoid stalling. As SeaFoam is an additive for your fuel and/or oil it may well fix any issues in the fuel or lubrication systems that are contributing to the problem but, it won't have any effect on a dirty throttle body or MAF sensor. May have to try both to solve your problem. Have never used SeaFoam so I don't know anything about what it does or doesn't do to an engine. Have never used any after market engine treatments so will defer to those that do.

Dadio, so you still have the problem or were you able to fix it? If fixed, what you end up doing?

It's markedly improved. I cleaned both the throttle body and the MAF as I had suggested you try in my ealiest post. With that said, my plugs are original and have not looked at the coils. Could be I would see a bigger improvement with new plugs and coils but car seems to be running fine and without the hesitation. Plugs might be a winter project. Next project is third radiator install, GT3 smile, and grills over all openings in the bumper.

Dadio, do you have a video or instruction on how to remove and clean throttle body? Want to make sure I do it correctly. Any information would be greatly appreciated.

http://www.renntech.org/forums/topic...ng#entry196485

The link above will take you to renntech post on what seems to be the same issue. One of the responses includes a link to a DYI on the process. While the DYI suggests Carburator cleaner for this process, I would suggest the CRC Throttle Body cleaner. Could be the two substance are the same but if you've got to buy it anyway, get the stuff specifically designed for the process. Carbs and modern throttle bodies aren't really the same animal in my book. Hope this helps.

Do we know if the BMC contributed to this issue? I have one and would be interested if these BMC's cause any known issues.

In my case, I don't think so. I had the filter in for over 15 K miles with no issues. After reading the DYI post I refernced earlier, the stuff that I cleaned out was the same as the poster suggested would be found. Based on that and the 2+ years I had no issues with it I've got to believe my issue was simply normal grime in the throttle body. Have recently cleaned and re-oiled the filter and will reinstall once I get an opportunity because I like the enhanced intake sound and Butt Dyno power increase. :o)