Audi TT 1.8T Misfire Rennsport Kansas City
Had this little Audi TT come in the other day with a running issue (bad stumble) and a misfire check engine light. The owner had diagnosed the misfire and put in a couple new coil packs with spark plugs, but there was no change.
A lot of times these Audi’s can have issues with low voltage, so I put the charger on the battery to see if anything changed, but the battery was in good shape.
I did find a bad diverter valve to the turbo, but changing that only made the issue worse as the boost was now where it should be, making the stumble more prominent
I tried to realign the throttle body with VagCom, but it kept giving me an adaptation error. Hmmm, not good, and a bad throttle body could definitely cause the stumble. I pulled it off and cleaned it, and untwisted the connector and reinstalled. Adaptation was successful after that. No change in running issue.
When I looked at the coil packs, there were a couple of aftermarket cheap coils, so I ordered up new OEM coils and spark plugs. The coil pack connectors were also ALL broken, so I ordered 4 repair kits for the harness. If the connectors do not sit completely clicked in, it can cause misfires.
And there were some broken wires which can cause voltage spikes and kill the coil packs, so the wiring was repaired as well.
After a lot of bending over and rewiring, we had a great running car! Success!