Wife's 1989 240 wagon, 130000 miles rusted thru side of exhaust downpipe. Replaced exhaust down pipe, brought to muffler shop (friend of mine) he welded a new pipe from down pipe to catalytic, with new hole for O2 sensor. Picked up car check engine light is on. Pulled code 221, faulty signal to and /or from AMM.
The car starts and runs fine for about 3 minutes. If you step on the gas, big hesitation, finally kicks in and backfires. It gets progressively worse and finally stalls.
Tried cleaning AMM contacts, replaced AMM with appropriate different spares- no change. Jiggled AMM harness while running- no change. Checked FAQS, changed out cap , rotor, wires, plugs, suppression relay, fuel pump relay, computers X 3, flywheel sensor, ignition amplifier.
Still getting code 221. Any thoughts and advice greatly appreciated.