Flat Spot - Just before boost

[PacWest]

My car did a strange thing the other day...

It started by surging a little at idle. Not always, but often over a couple days. Then, it had a miss at cruise, and even stalled once. After 2 days the SES light came on and I took it in to the dealer.

The dealer found the air cleaner was loose from the MAF. They gave me a little talk on my aftermarket CAI but no big deal. I should have checked that myself.

Now, it get's strange. The car is fixed regarding the above listed problems but it has a huge flat spot. Right before the boost comes on it falls flat on its face and then quickly jumps back to life. Furthermroe, the power seems down and it's just not quite its old self.

This goes on for the afternoon. I am thinking it's the boost by-pass or something - not that I know much about it. I look all over the engine and don't see vaccum hoses or anything out of place.

The next morning the problem is still there...big flat spot in each gear just as the boost comes in. By the afternoon it's GONE! I parked at work in the morning and came out in the afternoon and the car was back to normal. I was breaking them loose at 4K RPM in 1st again and the boost was nice and linear.

Just an interesting story to share - comments or ideas on what could cause the flat spot welcome.

-Ryan

 

[Whitten]

That is part of the wonders of modern day fuel injection. What happened to your car is what alot of people have happen to them, and something I have even delt with in my truck. My CAI came loose over a period of time and cause a restriction in airflow, and to some extent a vacume leak. The period of time that it happend was enough for the computer to begin compensating for the increased gap between the TB, loss of intake preasure, and the obstruction infront of the MAF being my filter. After reatactching the assymbly it takes time for it to be learned out of the computer, but after a few driving cycles it will figure it out and everything will be back to normal. Too many times people get scared about there car doing something along those lines and forget to check and see how tight there CAI is. I am guilty but learned a great lesson in thr process. Goes to show you patience is a virtue even with cars.

 

[JB]

might not help but since your MAF was being exposed to unfiltered air for awhile, it would be a good idea to clean the sensor wire...use electrical cleaner, spray it and let air dry