I have a 2000 beetle with AEG engine, 5spd, a/c, 89K miles. Have recently done a valve job after timing belt jumped and piston kissed 4 valves. after engine reassembly it starts and runs perfectly at idle but dies upon acceleration. scanner shows no codes. Oddly enough, if I disconnect the MAF sensor and remove the air intake tube from th air cleaner it runs much better but will not idle. I have also replaced the cat conv. thinking it may be clogged, to no avail. voltage and ohm tests on other components such as engine speed sensor, camshaft pos. sensor, ecm signal output etc. can find no other failures. does anyone have any ideas or should I just find a reliable arsonist!
any help will be appreciated
I've tried moving a tooth in both directions, no good. All 3 marks are now aligned at tdc. What is wierd is that I have an excellent idle but when it hits 2200 rpm it starts breaking down and acts like its getting no fuel. ( I just replaced the fuel filter and also tested fuel pump pressure- 60lbs) I have scanned it both at idle and when its breaking down at 2200 and it shows no codes. If the coil were faulty wouldn't it show a 300 -304 code? is there a possibility that an exhaust obstruction could happen behind the convertor? As before, if I disconnect the MAF sensor it will rev to 5K but I have no idle. [>:]

 

Bit late for a reply but..... a classic case of faulty airflow meter! A very common failure on late VW, Alfa Romeo, Volvo etc that use the same type of sensor. I fitted an aftermarketsensor to the last new Beetle that had this problem it can be very hard to detect thefault so one of those substitution tests.
There are a dew people that have successfully cleaned them so maybe worth a try if you get the same symptoms.
Cheers
Mike