Hi, my old wagon is having some trouble lately... it started months ago with a 2-1-2 OBD code for faulty oxygen sensor/signal. We kept driving as nothing seemed effected by it until recently. It started to idle rough and hesitate slightly for a minute or 2 after startup as if it were a carbureted engine on a cold day. However it is in the 90's and it's fuel injected.

After it "warmed up" for a minute or two it ran fine. However it got worse over the course of 5 days and then it failed to start at all. The exhaust smells of gas and I have been able to get it to start and it just chugs and sputters and then dies when I hit the gas pedal.

It seems to be running rich but I suppose it could also be a weak spark not burning the fuel so I swapped out the coil, cap, rotor, spark plugs, and ignition control module (plug wires are recently new). I also swapped out the oxygen sensor which was covered in carbon (wow is that fun) but still no change in how it runs. Which makes me suspect I'm barking up the wrong tree.

I do not smell or see gas in the FPR vacuum line. I do not see any cracks/leaks in the clean air tube from MAFS to TB. The intake manifold gasket is relatively new and appears in proper order. The TB was recently cleaned, the flame trap has not been cleaned in awhile.

I have not yet done a proper check of the ECT or cold start injector but I wonder if the ECT might be the culprit since it would run fine once it "warmed up". Does the ECT fail in this manner?

Will a failed cold start injector cause these symptoms?

Thanks for your help!



--
'91 240 wagon, '89 240 wagon, '90 740 sedan, '92 740 wagon