Join Date: Feb 2005
Location: Athens, Greece
Re: Flat spot at 4500rpm.....
Sounds like a MAF problem but could easily be a bad lambda sensor, a dirty throttle body or clogged injectors as well. I suggest that you go from the cheapest fix attempt to the most expensive ones, eg. first clean the TB, then the injectors and if that doesn't help check your MAF and lambdas.
At which point in the engine bay is the CDA fitted? Have you kept the length of the pipe from CDA to MAF similar to the stock pipe length from filterbox to MAF? Is there a chance that the CDA is getting its air directly from the front of the car, eg. is it fitted near a grille? IMO this may prove to cause problems because the intake system and ECU programming is not designed to handle ram air effect caused by getting air directly from the airflow in front of the car.
"Black holes are where God divided by zero." - Steven Wright