Just an update - car ran okay (not great) the next day after I cleaned MAF, then CEL came on driving home from work. Drove it to the shop across from work and told them I was thinking it might be the cat. They said code and their own diagnostic told them it was MAF. They replaced it and the car is running fine. THAT was too damn expensive... They tried to charge me $264 for part and $100 for labor until I showed them the part was $77 online and I could replace it in under a minute. Finally got away with $200 for the diagnostic and replacement but no one is happy - me or the shop manager.

Funny thing about all this is that the hard shifting has now gone away too - thank God!! I was becoming certain that a tranny rebuild was in my immediate future, now I'm back to thinking I might be lucky and never have to do that at all. Now I just have to worry about all the other sensors and I'm still wondering if I should have the cat replaced since it's the original and we're at 106,000 miles. How hard is a cat to replace? I just had the resonator replaced so that end of the cat pipe has fresh bolts.

 

Ive been thinking on this subject also.wondering if a shop could bend the pipe and make it long enough to deleat the cat and resonator .then drill a hole and weld a nut to the pipe to put the o2 sensor back in.I know I would have to install since its against the law for them to do that,I beleive. think it would work? i beleive it would breath alot better.
Brian

 

I had the same issues and my solution was the fuel filter. I had slow, bogging acceleration. Hard shifting, strange rpm's. Changed the fuel filter and that solved it. Thats a cheap spot to start at before doing anything extreme.

 

If you were going to take out the cat, there isn't a whole lot of point in going through the trouble to re-install the 02 sensor at another place.. That second sensor doesn't control how the car runs.. it's only a sort of indicator for when the car isn't running right and there isn't the correct amount of airflow.. Sooo, when you take out the cat, it will constantly be the wrong amount of airflow, causing the P0420 code..

 

The shop would be charged $10,000 for illegally deleting a cat.

 

Actually, I was just wondering how difficult it is to replace the cat w/pipes with a new cat w/pipes. I don't mind the cat being there, I just think after 106,000 miles it may not be working perfectly and possibly even hindering the performance of my car.

I will try the new fuel filter though.

 

yea I know its ilegal for them to instal it. but I dont beleive it is for them to bend the pipe.I know they make them for the mustangs for off road use only.just there way of staying legal.