Hello all, I have a 1993 audi 90 \. It is a v6 and has a terrible hesitation. If cruising at steady throttle it just cuts out. As if I loose 3 cylenders if held steady it comes back on. I am a professional auto technician, although experience with german imports is minimal. I have tested all of the systems that I can literally, this week I have put 20 or so hours into this with a labscope and all. I have nothing, It is killing me. Please help any ideas??? A few things I have looked at follow please tell me if I missed something; o2 voltage and response, knock sensors, fuel pressure, maf operation, ckp sensor, engine speed sensor, tps sensor, used propane enrichment to see if it helped, it did not, created huge vacuum leak to lean out, no luck, unplugged egr, used smoke generator to check for leaks, no luck, if any information will help with a possible cure I have it all from 02 volts to fuel pres to ckp pulse with, someone please help me.!!!!!!!!!!!!!!!

 

it can be also a iggnition coil, when crusing a wire goes bad, bum no power. its hard to know exact, unless problem persists. Also can be the EGR, try disconacting the thing, a hose on top, just use a bolt and close it up. check that to.