I have a 97 E250 4.2 that wouldnt get out of its own way. The clatter it made when you floored it was horrendous, sounded like the valve train had bad lifters. I also had a knock, when I shut it off it sounded like a bad rod, and thats what Pep boys told me.Nowthis motor was a jasper rebuild that really never ran right. The original motor had the harmonic balancer break off after I only had the van for 100 miles. I just decided to put a new motor in it because I needed a dependable vehicle for work. Well I drove this clattering knocking van for quite some time. Frustrated that it lacked power and ran like crap with a new motor. I got me a stethoscope and trace the sound to the exhaust pipe on the drivers side. specifically the catalytic converter. Now this knock really did sound like a bad rod bearing but it only made the sound randomly at idle and when you shut off the motor. Well I pulled off the drivers side exhaust pipe and turned it and powder came out of the cat. I knew then ther was exhaust restriction. I shook it a few times and out comes a chunk of the guts to the cat. A chunk of ceramic or platinum or whatever its made out of with long small holes in it for the exhast to pass through. Taped it on the ground afew good times and a bunch of fine particles and dust comes out. Well I ordered the whole piece from autozone for 300.00 or less and it will be here tomorow. I beat the old cat with a hammer to bust up all that was left in the cat and emptied it out. I put it back on the van and PRESTO my van ran like it never has before. Shifting was now smooth and I didnt have to let off the gas for the shift to happen. The acceleration was really improved and no more spark knock or rod knock when i shut it off. Oh what a good feeling when a problem you have been living with for months is resolved.

 

hi, well thats what i call a good result. i wonder how many of us are running with duff cats and poor performance thinking its normal. bokker.

 

Not too uncommon to have the older, high mileage cat converters come apart.
Glad you found it, and another good example of the value of a mechanic's stethoscope.

I honestly think it is one of the most under utilized tools around.
Cheap to buy, but priceless in some situations.

Thanks for the update!

 

I've got the same problem with my 2001 e-250 4.2l. but I put a pressure guage on the O2 sensor hole, and there's NO back pressure....It won't get out of it's own way...no codes....anyone have a hint as to where I should look now?????