Almost back on the road...


Active member
Nov 15, 2018
2004 Passat
I am close to being able to claim to have driven a well running TDI. But need some insight. Here is the situation:

EGR fell off, coolant flange replaced, new shocks/struts, new pads/rotors, new alternator, new headlights, new trunk struts, new hvac fan and resistor, cleaned intake manifold and actuator... I have never seen an engine with that much carbon build up. It took 10 hours, 2 full cans of oven cleaner, a screw driver, Dremel, and pressure washer to get as clean as possible. Over 1/4 thick deposit in the location I measured. Got it all back together to find that I resolved all of the trouble codes I was getting. But now the car drives worse (didn't think that was possible) and a new code.

P0299 Underboost. I hooked up my microscan and looked at live readings. Everything looks good except the MAP. MAP reads 0. Car also coincidentally drives like a naturally aspirated turd box. I've been doing a bunch of reading and figure it is most likely stuck turbo vanes (assuming it has similar carbon buildup as the intake, egr, and actuator).

Anything I should check before the turbo? Anything magic to "cleaning" the turbo? Other than avoiding the screwdriver and Dremel...