This past week I have had issues with my cars acceleration only in the afternoon-late afternoon it is very strange,It feels like no boost(35 minute drive to destination). It is not tripping any CEL.

The car runs perfect at night or just getting dark when it is cooler out. (driving about 20 minutes)
It averages about 80-90°F outside temperature in the afternoon, 70-80°F early night.

Not Chipped. 70k miles.

• I have no strange engine temp readings on cluster
• Cleaned MAF
• Boost Leak Check
• Cleaned AIT sensor
• Used Vag-Com To read MAF at idle, was reading ok(3-4g/s), did not check MAF with acceleration.
• Cluster reads 14-16 MPG when I have no acceleration, 22-24 MPG when car is running good.
• Cleaned AIT sensor.

Im wondering if anyone else has had this issue or has any idea what I can check before I go off buying all new intake-fueling parts.

Could it possibly be the thermostat not working properly?
Possibly 02 Sensors?
What parts could fluctuate my cars acceleration due to temperature?

Please help .

 

Just on the off-chance, several of us near me have had trouble with e-brakes binding up and not releasing. Notice any burning smells lately? After a drive of at least several miles, see if the center of one or both rear wheels is noticeably hotter than the others.

 

After a 60 mile drive all wheels feel about the same, front tires just a little bit hotter,no strange smells of rubber.

 

Have you figured out the issue? I think I'm having the same problem.