I recently had a trustworthy mechanic diagnose and replace a faulty AMM. The car had been starting hard and running rough. The new AMM fixed both of those problems immediately. But now the car has a 'bumpy' idle, that is it runs a little bit rough, but not on the verge of stalling. When I give it some gas it runs fine. And - the big problem is - now I'm getting half the MPG I used to, barely 100 miles to a full tank. The exhaust smells very strong of gasoline.

I am one click away from buying a new oxygen sensor from IPD for $150. But before I do, I want to confirm the symptoms as being that of a faulty oxygen sensor. I don't have the money to pay a mechanic and the fix seems easy enough for me to do myself. I was quoted at twice the cost of the part to have it done.

Any thoughts before I spend the $150?

Check the fuse for that circuit. I just recently solved an 02 sensor issue by removing a corroded fuse and cleaning the fuse panel. I'ts fuse no 4 on my 90&91. Check your fuse panel cover.

I pulled the sensor and wiped the black soot off, then I checked the fuse and found the corrosion. Check engine light went out and stored code dissapeared.

Good luck.

S.

It's not likely the oxygen sensor, which is $40 for a splice-in most anywhere.

Yes, I saw those but is it wise to replace with a sensor that is not the recommended one for the car? I have heard conflicting opinions on this.

Archie-

I just replaced the original 02 sensor on my '89 240 with a Bosch #13913 today. I spliced the wires into the wiring for the old sensor. It works flawlessly. Confirmed with multimeter testing. You are basically paying $90 for the two connectors at the end of the wiring when you buy the "correct" part.

Check the vacuum hose on the fuel pressure regulator, does it smell like gas? If so the diaphragm in it may have failed. Dan

It does smell like gas. Thanks for the tip.