Engine Performance problem
2000 Jaguar S-Type 6 cyl Two Wheel Drive Automatic 87000 miles
My 6 cyl. Engine in my 2000 Jaguar S-type has begun to run poorly after starting & going through the warm-up cycle. I bought an engine code analyzer that indicated both banks were running lean and the code suggested the MAF sensor. I unplugged the MAF sensor at idle and the engine ran fine. I replaced the MAF sensor with a new unit and the results were the same - poor idle after warm-up & the engine " clears-up" if I unplug the new MAF sensor. What does the MAF sensor communicate with to make the car run efficiently or am I overlooking something else (ECM)? What is the probability that the new MAF sensor is bad?
Lean on both banks is often a vacuum leak in the common intake area. Inspect all vacuum lines that connect to theintake manifold, also closely inspect the intake boot from the MAF to the engine. Any vacuum leaks in these areas will cause the engine to run lean. You can also try carefully spraying the intake area with carb cleaner while the engine is idling, if the engine changes when you spray an area, you have found a leak.