[AZWildcat]

I'm wondering if anyone has had a problem like this and what the remedy was...

After a drag strip pass, the car began a very choppy idle. When gas is applied, the car will bog and fall down. Bliping the throttle several times normally brings the car above 2k; when it is above 2k, the car revs normally.

On the street, if a light load is applied to the engine, the car will impose a 5k rev limiter. Under very slow acceleration, it will go to redline. The car will come on boost, but will not move anywhere... I assume the computer is removing all of the timing. It is showing code 55 (rear knock sensor) and code 13 (cam angle/crank angle/sync error/lost timing). I am going to use the oscilloscope on the car tonight to see how the sensor is working, but has anyone had this and what was the problem? Thanks.

 

[BoostedToy]

Dennis,
This might be at least somewhat relavent. I had an MKIII turbo(fairly modded) with the same symptoms that you do. I had a code 53(rear knock sensor). The car had a choppy idle and i could rev the car up if the engine was not under load( it would free rev slower than normally though). If i would go to WOT the car would fall on it's face and it acted almost as if it had a rev limiter. The timing was backed off so far that it was not burning the gas and was running extremely rich. If I ran lower boost levels(6-11/12psi) the car had this problem as i forementioned. If i ran 13-16psi the car would get out of that "rev limiter like" state it was in. It still would not pull like it should(timing was backed off more than normal. I had a HKS FCON in the car for a different fuel map/tuning ability. I removed the FCON and the symptoms went away(even though the car still had less power...knock signal was still being sent).I figure you have larger injectors and some type of fuel enrichment. I am sure the MKIV has different safety modes than the MKIII.This might be along the same basic lines though.Maybe this was of some help...if not...i tried.