Steve knows what he is talking about. I had a similar problem and he knew exactly what was wrong.

I dont know what state steve lives in, missing location from the id on the post.

But, I tell you guy like him you dont need to worry about car being fixed. I always worry and nervous when I bring my car to the Mechanics. I wait around and watch.

It would be nice to drop off your car and know the person who is fixing the car is good.

Had the mechanic reset the fuel trim adaptation value after the Mass Air Meter replacement (P0170). Two days later, the check engine light came back again. The car drives fine without the loss of power at 40% throttle as stevebfl stated on earlier post. What's next?

Delta
97E320

Go to Autozone or your mechanic have the code read if same as before reset 1 more time, also check the gas cap.

Merc1,

I scanned/resetted the codes numerous times and the same codes always come back (P0170 and a pending code of P0130). The cap was checked as part of the calif. smog check about 3 months ago and it was fine. I did have the reduced performance prior to the Mass Air Meter replacement. After the replacement, the car ran better with no reduced performance at 40% throttle as stevebfl stated. Any more suggestions?

Delta

Update:

I think I found the cause for my check engine light (P0170). I had previously replaced the MAS and reset the fuel trim and the check engine light still came up with the same code scanned. Yesterday, my car had a very irratic idle when stopped at a light. The car was shaking badly with idle fluctuate between 300-700 rpm and it seems lilke it's going to stall. I took it to an independent mechanic and I watched as he diagnose the problem. After inspecting the car, he decided to spray some carburetor cleaner on the intake manifold. As soon as he spray around the intake manifold, the idle smoothes out and he determined that there's a leak. We soon discoverred that a flap on the manifold broke loose (I am not sure what the part is called). I think the flap opens/closes to adjust the air flow into the intake. As soon as it is replaced, the car idles and drives perfectly.

As I inspect the broken part, I was amazed at how flimsy the part was made. The flap and the surrounding pieces are made of plastic and does not look robust at all.

Hopefully this ends my check engine light saga. Thank you all for the help.

Delta