I just got my '93 MKVIII tuned up, but a recurring prob. will not go away. The car hesitates and vibrates/bucks when accelerating in a high gear while in traffic. The check engine light comes on, too. I have taken this to a shop, but the car doesn't do this all the time, so it's hard to catch it in the act. In any event, I need to take it back but I don't know what to tell them to look for. I don't know what the code would be, either. Anybody else have this happen?

its your 02 sensor

its your 02 sensor

I was afraid of that...

I would check the codes it might not be oxygen sensors. Who knows what it is what type of tune up did you do? Could be an ignition problem or maybe a fuel problem.

I would check the codes it might not be oxygen sensors. Who knows what it is what type of tune up did you do? Could be an ignition problem or maybe a fuel problem.

I had a tuneup, oil change, all filters. Then I had the injectors flushed. Decarbonized combustion chamber and cleaned fuel rails, screens, intake valves, and manifold. Replaced throttle body assy (bad idle), idle control valve & gaskets, cleaned throttle plate & idle air bypass. Serviced trans., flushed cooling system and brake system.

The codes I had were:

176 - EGR not switching, lean exhaust bank 2
177 - EGO not switching, rich exhaust bank 2
524 - Low speed fuel pump circuit open
543 - Fuel pump circuit open, battery to ECA
634 - Manual lever position sensor out of range
412 - Cannot raise RPM - extended idle
411 - RPM out of spec - normal curb idle

I called my mechanic and he doesn't think it's the O2 sensor b/c it didn't show up in the codes. I told him the car doesn't do it all the time but he said it is all in what the codes say.

Bump

have you checked your fuel pressure?

have you checked your fuel pressure?

I have no idea how to do that, I'm not a mechanic. I'm trying to learn.