VW Atlas Poor Acceleration & High Fuel Use Needs Fix

Had nearly identical symptoms with my 2020 VW Tiguan. The rich mixture was causing excessive fuel consumption and inconsistent performance. Multiple diagnostic tests revealed a faulty fuel injector that was dumping too much fuel into the cylinder. The air-fuel ratio was completely off balance, confirmed by readings from the oxygen sensor. What started as slight hesitation during acceleration quickly developed into serious performance issues. Main repairs required: Replacing the defective fuel injector, Cleaning remaining injectors, Testing oxygen sensor function, Verifying air filter condition, Checking spark plugs for fuel fouling This was not a minor issue, running with a bad injector risks damaging the catalytic converter and engine components due to fuel washing down cylinder walls. The repair required specialized diagnostic equipment to identify the problematic injector. The complete fix took about 6 hours at the shop, including testing. Recommend getting it checked soon, as continuing to drive with these symptoms could lead to more extensive damage. Worth noting, after repair, fuel economy returned to normal and the hesitation completely disappeared. The check engine light also cleared and stayed off.

Thanks for sharing your experience with the Tiguan injector problem. Really helpful details there. My Atlas had similar symptoms but it turned out the intake manifold had a small crack, which was throwing off the air-fuel mixture and triggering the check engine light. The oxygen sensor readings were all over the place before they found the actual issue. My mechanic first checked the air filter and fuel system but eventually traced it to the manifold problem. How much did your injector repair end up costing? And has everything stayed running smoothly since the fix? Just curious if you had any other issues pop up afterward.

Glad to share a follow-up on my Tiguan repairs. The faulty injector was indeed causing the rich fuel mixture, and fixing it cost 515€ total. The air-fuel ratio is now perfectly balanced, and fuel economy returned to normal levels, a huge relief after watching it gulp down fuel before. The oxygen sensor readings have stayed consistent since the repair, proving it was definitely the injector causing the erratic behavior. The engine runs much smoother during acceleration, and the sluggish response is completely gone. No additional issues have emerged in the months since the fix. The intake manifold, air filter, and other components all checked out fine during the diagnostic process. It was purely the injector dumping excess fuel that caused all those symptoms. Interesting that your Atlas had a cracked intake manifold, that would definitely cause similar symptoms. Both issues mess with the air-fuel ratio, but thankfully once identified, they can be properly fixed. Running too rich can cause serious problems if left unchecked.

After trying different shops, I took my Atlas to a certified VW dealer. They quickly diagnosed the cracked intake manifold that was causing the rich mixture problem. The repair took about 4 hours and cost 780€ including parts and labor. The mechanic showed me where the manifold had cracked, explaining how it was letting in extra air and throwing off the fuel mixture. They also checked the spark plugs and air filter while doing the work, both were fine. Three weeks later, everything runs perfectly. The check engine light is off, acceleration is smooth, and fuel consumption is back to normal. Having the right diagnosis made all the difference, no more guessing about fuel injectors or sensor problems. A good lesson learned about getting proper diagnostic testing instead of assuming the common causes. While injector issues often cause similar symptoms, having specialized techs who know these engines made the real problem clear quickly.