Flatspot at 3000-3200 rpm

[Box4two]

So I've been doing some work to my 2000 Boxster, some that was needed and other stuff just preventive maintenance since I didn't have much previous service history on this car.
Had a cel which ended up being a Maf, changed it and no more cel.
Warm starts always gave me a rough idle for 30 secs and misfire code, so changed all coils and plugs, problem solved.
The car has 50000 kms and was now running perfect through the entire rmp range.
Lastly I decided with all this work done I might as well clean the TB, so I did, it wasn't too bad and no excessive oil from AOS that I could see, but now.....it has a noticeable flat spot at around the 3000 rmp mark, mostly noticeable at half to three quarter throttle.
I did the E GAS reset, but no change.
I also read that the caymans seem to have this issue and it's quite normal, but mine wasn't doing it until now.
Any thoughts on this?

[Box4two]

Am I the only with this problem?

[tommy583]

I sometimes have a flat spot around 5000 rpm at wide open throttle. I have changed the MAF, AOS, plugs and checked for vacuum leaks. I noticed when I disconnect the battery to do electrical things, I don't seem to have the flat spot when I hook it back up. It does seem to come back after a while though.

I don't have any active or pending codes using an Actron scanner. I hope to get a Durametric cable this winter. Maybe that will help me figure it out. Sorry I couldn't be more help.

[Box4two]

Thanks for the reply, the only thing I can think of is since this happened after cleaning the Tb, I must have left some dirt, residue somehow, or created some sort of vacuum leak on installation. I'll clean it again, and also try disconnecting the battery, maybe it does need a reset.

[seningen]

Originally Posted by Box4two

Thanks for the reply, the only thing I can think of is since this happened after cleaning the Tb, I must have left some dirt, residue somehow, or created some sort of vacuum leak on installation. I'll clean it again, and also try disconnecting the battery, maybe it does need a reset.

You can search for a vacuum leak by spraying carb cleaner that is combustible around your intake area and see if it changes idle momentarily.

In most trouble shooting issues where something has been touched
I focus on that area first.

It would seem too much of a coincidence otherwise to just start a new problem.

You might also try cleaning your MAF


Mike

[Box4two]

I checked for vacuum leaks and none were found, so I decided to clean the TB again, and since my hands were in the mud I also cleaned the MAF (this new Maf was installed about a month ago) retightened all the connections again, went for a test drive and it's smooth again through the entire rpm range.
So I'm glad it got resolved, but I hate that I couldn't single out the problem.

[clickman]

Is the new MAF OEM or aftermarket? IIRC some people have had issues with aftermarket MAFs.

[Box4two]

Originally Posted by clickman

Is the new MAF OEM or aftermarket? IIRC some people have had issues with aftermarket MAFs.

Hmm.......yup, aftermarket. I if happens again, this time I will just clean the MAF and maybe able to pin point the source.