csmlet

I am looking for some advice, have a 2006 F150 4X4 with 75,000 miles. A couple of months ago I began to notice a shudder when accelerating from a no load speed. Got my transmission checked at transmission shop and was told there wasn't a problem with the tranny. He told me it was a cop but since there was no code just to drive it until it threw a code and he could tell which cop was bad. After 2 months, still no code and shudder is worse plus now it has no power when you step on it to make it go into passing gear. It literally bogs down but runs fine otherwise. I took someone's advice on this forum and cleaned my MAS. Followed the instructions to the letter and after cleaning it my check engine sign came on. Took it to Autozone and they checked it and it was code P 0420 which is the left catalytic converter. Cleared the code and after 2 days it came back. Just put an additive in the fuel tank that supposedly will clean the cat sensors. Will see if that helps. Don't know what else to do except replace all cops which is fairly expensive. Anyone have any suggestions? Thanks one and all.

SCORGE

May be time to Change plugs and cops. I would think the only reason a cat would go bad that early...is it's been misfiring for awhile...and clogged it. Just my thought...could be wrong. Might be a faulty 02 sensor as well..? If the cat is clogged...it should be glowing a faint red after normal operation of the vehicle

csmlet

Thanks for the quick reply. My mechanic said to just drive it until it throws a code for cops and then he can tell which one is bad. Think I should do this or just replace all of them?

Martian

$40 on Amazon for a set of Chinese coils and you're done.

SCORGE

you could do that...but...if the plugs haven't been changed before..I'd do it. Ford now recommends 60k miles for plug change due to the major PITA that it can become. Buy Motorcraft plugs.. SP-515
And the longer you drive with a misfire...the more other things can become affected. Then get your coils from Amazon. Do it all now...peace of mind

Martian

Ohhhhh yes. My plugs took twelve hours to get out. Didn't break any, though.

csmlet

Talked to my mechanic again today and he said to unplug the MAS and drive it, it will show in limp mode and will be sluggish but if it doesn't shudder and pop back through throttle body then I need to replace the MAS. I did, and it did just as he said so bought a new MAS and works fine, for now. Will see how long it will last, as of now runs good and no codes.

k_h

Have you checked the Fuel Pump Driver Module above the spare tire?