VW Bora Running Rich: Common Fuel Mixture Problems

As someone with some repair experience, I had a similar issue with my 2002 VW Golf with almost identical symptoms. The main problems were rough running, high fuel consumption, and power loss. After diagnosis, the problem turned out to be faulty fuel injectors. The mechanics found that one of the injectors was stuck partially open, causing the engine to run too rich. This was affecting both fuel economy and engine performance. The repair involved: Testing all fuel injectors, Replacing 2 defective injectors, Cleaning the intake manifold due to carbon buildup, Installing a new air filter since the old one was contaminated Total cost was 515€ including parts and labor. After the repair, the engine ran smoothly again and fuel consumption returned to normal. To help diagnose your case more accurately, could you provide: Engine size and type, Current mileage, Any recent maintenance history, Whether you notice any black smoke from exhaust, If there are any specific error codes showing The symptoms you describe could indeed point to fuel injectors, but could also be related to other components in the fuel system. Getting this additional information would help narrow down the possible causes.

Thanks for sharing your experience. My car has 79695km on the clock. Your fuel injector situation sounds quite similar to what I am experiencing. I pulled the error codes and got P0172, which confirms the rich mixture condition. During my last service they did replace the oxygen sensor, so I doubt that is the culprit. The catalytic converter also looks clean from the outside with no visible damage. I am now thinking to have the intake manifold checked since there could be carbon buildup affecting the air flow. Will also request they test the fuel injectors while they are at it. Could you share roughly how long the repair took in your case? Just trying to plan ahead in case I need to leave the car at the shop.

Thanks for those details. In my case, the complete repair took about 6 hours at the shop. The biggest time consumer was cleaning the intake manifold, as they had to partially disassemble it to properly remove all the carbon buildup. The P0172 code you got matches exactly what I experienced. Since your oxygen sensor is new, focusing on the fuel injectors and intake manifold is a smart approach. When they fixed mine, they also performed a fuel system cleaning to ensure optimal fuel delivery after installing the new injectors. Looking back, these were the exact improvements after the repair: Check engine light disappeared immediately, Fuel economy improved by about 25%, Engine ran smoothly with no more jerking, Power delivery became consistent again Make sure they perform a proper fuel injector test rather than just cleaning them. In my case, cleaning alone didnt solve the issue because the injectors were mechanically faulty. The intake manifold cleaning made a noticeable difference in how the engine breathed and performed overall. Given the similar symptoms and error code, I would bet you are dealing with the same underlying issues. The repair cost might be comparable to what I paid, depending on how many injectors need replacement.

This should help everyone understand what could be wrong. The P0172 code combined with my symptoms definitely suggests fuel system problems. I will book the car in next week and request both injector testing and intake manifold inspection. The 6-hour timeline helps with planning, I can arrange to leave the car for a full day. If the repair costs end up around 515€ like your case that would be manageable. Good to know the check engine light cleared right away after fixing it. I will make sure they do proper injector testing rather than just cleaning. Makes sense that cleaning alone might not fix mechanically faulty injectors. The rich mixture needs to be addressed properly to avoid damaging the catalytic converter down the line. Thanks for sharing your experience in detail. Will update once I get the diagnosis and repair completed. Hopefully replacing the injectors and cleaning the intake manifold will solve my fuel economy and performance issues just like it did in your case.