Audi Repair Questions? Ask a Mechanic for Answers ASAP
Hello! My name is Gary.Welcome to JustAnswer.At 249000 miles, I would say it is potentially due for an engine rebuild.
But the first things to do is check and replace timing belt as necessary, and a top end carbon clean.
A worn stretched timing belt gives sluggish performance and can log MAF codes on many cars.
Have you ever performed an upper cylinder clean on this engine?
With Sea foam, Subaru upper engine cleaner, or AC Delco etc.
Makes a surprising difference to the throttle response etc from decoking the cylinder head this way.
I you are confident the timing belt is correct, that is the main thing.
What code was set for the MAF sensor?
The carbon buildup I'm talking about is in the combustion chamber.
Starts at the back of the intake valve.
You could have an unmeasured air leak, post MAF, crack in airflow duct etc.
So lets see what code you had please.
Either of those spark plugs should be ok for you.
Is your intake, airbox etc all factory?
MAFs don't like oil from air filters.
I don't run k&n on any of mine now.
I run AEM Dryflow.
I'm happy you are still running factory airbox.
Have a look at the duct you have mentioned especially hose clamp points wear the duct could gather.
The convoluted duct could be split.
Yes ok, that's fine, just come back when you are ready.
Sounds like you a well looked after example.
I can understand your slight frustration.
Good night for now.
The large hose is how the engine breathes, MAF to throttle body.
The two smaller hoses are from valve covers, crankcase breather hoses.
I'll let you sleep now.
It is only 8.15pm for me.
For how well the car goes at the top end, it won't be a spark plug or lead.
I would say the difference between cold and hot has a bearing on the outcome.
I have a Scangauge on one of my cars, that shows me any data I care to look at.
Yours could have a faulty coolant temp sensor, or a split in a air duct.
Analysis of engine data on a screen, which means a passenger with a scan tool logging data for post roadtest, would help here.
I have done this many times with workmates.
Saves just guessing.
Do you need any further help?
I hope my advice has been of assistance to you.
Are you about to look at your car again soon?
Your problem is a hesitation flat spot on acceleration, or surging under 4000 rpm?
Maybe there might be an ECM reflash update available from AUDI.