230K B230FT

This car has been running great after a headgasket replacement that included freshing up the head. It had a clean up cut and I lapped the valves about 4000 miles ago. The check engine light has been coming on indicating lean/rich conditions. It was off for a good period after replacing the o2 sensor only to come on again and then go off when I cleaned the throttle body... only to come on again several hundred miles later. So it has been on for a few thousand miles.

Round trip of 700 miles. Checked mileage on first leg and was pleased to see it was 26+. The only complaint I have had since the headgasket work has been the check engine light and a "loping" idle. The idle control motor seemed to be working properly. Cleaning the throttle body did not solve the problem.

On the return leg the car stalled several times after an initial startup when I put it in gear. Otherwise things seemed to be normal. When we got about five miles from home the car died as I tried to pull away from a traffic light. It started right up but then stalled a short time later. This stalling problem persisted. It died at speed several times but caught again as it was coasting down. I noticed that the tach still registered as the engine lost power.

The last several miles were touch and go with stalling but with a quick startup only to stall again upon any effort to accelerate. I was able to get back to our residence and coasted into the garage.

Next morning I swapped out the fuel injection relay and expected it to be fine, but it was not. Now the symptoms were a quick start up but as I tried to rev the engine it would backfire through the intake. I did a quick check of the fuel pressure and it was spot on and the fuel pressure regulator responded correctly when I pulled the vacuum hose. I had convinced myself that the problem was fuel related but things seemed to be checking out.

With the check engine light on all the time I was not alerted to other things that might cause it to go on so I pulled the codes. The lean/rich codes were there, but there was also one that pointed to the AMM. I had a spare in the travel box in the trunk so I put it in place and that solved the problem.

I don't know when the AMM would have caused the check engine light to go on but perhaps it would have gone on when it started stalling on startup on the return trip. After replacing the AMM I had the opportunity to fill up the fuel tank and when I checked the mileage for the return segment of the trip I found it had dropped to 21 miles per gallon.

After replacing the AMM I no longer have a loping idle.

Randy