Rough Idle, bank 2 stuck rich - just solved head gasket for now!

Good day. This is a new post after 1st issue solved. 186K on my son's 2003 Expy. Small head gasket leak causing overheating and poor idle, etc, Fought it for a month and finally used some Blue Devil head gasket sealer and it seemed to work. Will say more about that at end!

MY CURRENT PROBLEM - After all the combustion problems caused by the head gasket leak, the Bank #2 O2 sensor was continually trying to fix the fuel ratio problems and finally went to "P2198, Stuck Rich. The OBII readings on bank #2 were all over the page, ie -14, +23 etc etc. as it tried to compensate. Now that the head gasket issue is resolved, it still idles terribly and sputters on acceleration. Although hiher speeds aren't that bad.

Although I read that O2 sensors don't go bad except for connection errors, I find that hard to believe. With about a month of coolant, bad fuel mixtures etc running thru the sensor, is it possible that the sensor is just bad at this point and reading properly. I have replaced all the plugs and checked every COP and replaced 2 that were questionable. FORD says that it is very rare to have a bad injector on Expy's.

Finally, to those that think I am nuts, NO, I would never use a head gasket sealer EXCEPT for this situation where my boy just needs a year out of the car. As most of you know, being a 2003 EXPY, the only way to really replace the head gaskets is the remove the engine and as you also know, EVEN FORD finally realized that it's easier to left the entire body off the frame that remove the engine via the front or bottom! At 69 years old, those days are over for me and the car isn't worth paying to have it done!!

Thank you for any comments!

Hey mark, Moose here. Well you found out these crazy SUV problems. Their are ways to test the bad o2 sensor but you might want to just replace it. And yes the injectors do fail. Usually stuck open. I'm 61 myself and know what you mean about messing with these beasts. I'm impressed that you temporarily stopped blown head gasket leak. It is temporary. Like stopping a major blood loss in a human, you got to operate and stop bleeding. I've never seen any of these fix it items work. Their all temporary at best. If you've got 12 months, that you need this SUV to last I your a religious man. Stranger things have happened.


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You may be old but you need to pass on to your son your mechanical skills. At least he'll remember you by that. Don't waste money on the gasket sealers. The only way is head gasket replacement. As for your O2 sensor problem, You might want to use a scan tool to verify O2 sensor response. With the engine warmed up, disconnect a vacuum hose and see if the sensor goes lean. If it does not, check the wiring to that sensor. If that's good, then you probably have a faulty O2 sensor.