That's because the blown plenum screwed it up, which doesn't effect the heater itself Plus the fact that the original(MOPAR) only lasted 23K, maybe even just cleaning it would have fixed it.

 

It's a rare issue , even with jeeps . Most common in the 4.0l straight 6 . No plenum issues there . Cleaning will not fix this issue , it's been tried , simply a malfunction in the sensor during a certain part of the cycle . If you've ever witnessed it , you wouldn't forget it , it's just that wierd . Never did see it on the V8 myself .

Yes , the plenum issue is very common , but , not the root of all evils either . My plenum is shot , pings like a mother . Cat wasn't clogged (recent ), just rattling , and the 02 was normal in appearance when the cat was removed and a joiner installed with the bung and O2 . I just bought the hughes plate kit , the engine was never taken apart that I can tell , 180K , started pinging about a month after I got it , and gave it a hard run in the mud . Oil consumption went fr 1/2 quart after 3000 miles to 1 quarts per 1000 miles . Easily noticed and luckily caught before running out , lol .

If the OP complained about oil consumption or pinging , then I would agree , blown plenum . but he didn't . OP , it's a fantastic upgrade to get a hughes plenum plate before anything starts to leak in the plenum , it's bound to fail .