jaydubb13 0 Posted April 24, 2015 Report Share Posted April 24, 2015 I have a 2003 gti vr6 with a ghost no one can figure out. Not the dealer or various local vw experts. I don't want to give up on my car. Only fault is rear 02 and the mil stays on for that no matter how many different sensors I try. Car runs ok when cold. When hot hard starts warms stalls and runs like shit like she's dying. Barely goes. Pedal to the floor nothing, then she will kick in out of nowhere . dealer said it was maf. I have 4 sensors in a month. I notice change immediately but as soon as car adjusts to new sensor back to old ways. On a scanner my numbers look great. Nobody spends enough Time with her to experience the problem when she's really hot. Not coolant temp problem either. Fuel pressure fine. I even tried a new ckp thinking it was failing intermittently. I'm going to swap ecus to see if a new computer helps. The dealer Has flashed mine no result for warm stall issues. Any one who has had similar problems please Help this problem is causing major stress in my life I'm obsessed with getting to the bottom of it. Thanks jessica Link to post Share on other sites
c00k 435 Posted April 24, 2015 Report Share Posted April 24, 2015 (edited) Vag-com and measuring blocks, (Not a Handel held diagnostic machine) Full vag-com or full VCD's on a laptop. Use the measuring block on every single sensor, measure them once when cool and running smoothly, and once again when hot, and running rough. Look to see any differences between the sensors results. This would be me starting place. Depending from results of the measuring blocks, Compression test when cool and when hot again. Depending on results from compression test, leak down test when cool and when hot. There are vag-com and VCD's specialist out there. Not just a VW specialist a VAG-COM specialist.Could be a faulty ECU, if brand new sensors are playing up. Could also be wires to a sensors, Check all wiring to all sensors, check all wiring to ECU. Edited April 24, 2015 by c00k Gwr corrado and D11PS 2 Link to post Share on other sites
jaydubb13 0 Posted May 3, 2015 Author Report Share Posted May 3, 2015 So I'm swapping ecus seeing if that works. Checked the wiring. Seems ok. There is no signal coming from the ecu to my o2 sensors is what I've discovered Link to post Share on other sites
jaydubb13 0 Posted May 6, 2015 Author Report Share Posted May 6, 2015 Ecu was the problem. My car runs like a brand new car. Edu wasnt sending signal to o2 sensors. Problem solved Link to post Share on other sites
HopefulVr6 10 Posted May 7, 2015 Report Share Posted May 7, 2015 (edited) When you said it was going wrong after it was learning I was thinking the ECU. I think the "non-volatile" memory in the ECUs can degrade such that the data gets corrupted and it can cause weird effects on things the ECU is trying to control using that data. I have seen that on other VW ECUs of that age. Bit worrying really in case after x amount of years they all start doing it! Of course could also just be that the o2 sensor outputs had fried for whatever reason...! Edited May 7, 2015 by HopefulVr6 Link to post Share on other sites
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