Consistent hesitation/lurch/flat spot at 1500 rpm until engine warms. No faults register. No improvement with reprogram ignition softeware. Any insights?
Thanks.
Porsches do not like to be "lugged". Give it some boot and you will be fine. i.e. don't baby it.
Wait till it warms which should be less than 1 min.
Best way to warm it up is - just drive! Give it a little more gas, get the engine over 1500 rpm. I learned the hard way (and with lots of practice) in my 914. Little 1.8L engine only develops about 90 hp but LOVES to rev up from a cold start, not sitting idling.
That is not the applicable to modern day engines, I think. I personally like to drive for 5-10 minutes before I let her loose. Just to make sure the oil has reached a higher temperature (than cold!). But of course each to his own, one of my neighbours has a really nice sounding e92 M3 (with complete A.C. Schnitzer exhaust) and it always gets revved hard when it pulls out of the garage...
Oops - evidently gave wrong impression here. Don't mean red-lining it, which on the 1.8 L is only at about 5,800 rpm. The 914 doesn't put out much torque, so it is very easy for the engine to "lug". I've learned to "feel" how 1st gear responds as I let up on the clutch and press down on the accelerator.
Try cleaning your MAF sensor it may have oil residue on it as a result of the oil ingestion problem. My car was experiencing the same problem at cold idle and a decrease in power at 6000 rpm's +, the difference was amazing after cleaning it. You can get the cleaner at Pep Boys Made by CRC $6.
Thanks for the replies. Lugging is not the problem - hesitation lasts 1-2 second only but threatens stall when you're in someones way. 1 minute warmup won't fix it - warm engine will. Hard for me to understand how MAF could be responsible at 1500 rpm for 1-2 seconds.
Dealer has verified this as a problem in my car - can't fix it. Never saw this problem before.
Thanks.
MAF sensors increase or decrease fuel delivery based on changes in temperature across the sensor which is affected by air flow which is in turn dependent upon engine speed and throttle plate position. If the very temperature sensitive plate or wire is coated with a foreign body such as dirt or oil (insulating it) it will fool the sensor into thinking that the airflow is less than what it actually is. This in turn will create a temporary lean mixture which will cause hesitation/ rough running and a decrease in high RPM power, other computerized systems try to correct this based on engine load and throttle plate position but it is not as effective as a clean sensor. Hope this helps, if you have oil in your intake system around the MAF then it is possible it is being affected, try cleaning it it takes little time and the cleaner is cheap. Since Porsche seems to avoid the oil ingestion issue and possible repair expenses, I'm not surprised that the dealer would not be aware of a potential MAF sensor issue related to oil contamination. Good luck!
