Hello, I have an O3 Escape that I just replaced two catalytic converters and gutted the firewall cat (to see if anything changed). I did this because I felt it was worth a try, since the exhaust manifold on the rear had three broken bolts. Anyway, after I gutted the cat, I got no engine lights like I normally did (multiple misfires). I decided to take it down the road, and it did fine for about 1/8th mile, then lost power like the transmission was bogging down or something. The engine would not rev and eventually I got it home on 1300 rpms or so. The slightest hill would make me wonder if I was going to get it home. Again, there are no exhaust restrictions. Any thoughts on what might be wrong? All the COPS are new. Vacuum lines look bad, but I can't hear or feel any leaks. Thanks.

 

Don't know if this is the problem, but if the aft O2 sensor is not working correctly or providing correct info to the computer ,it is capable of placing the vehicle in "limp mode" which is limited power .

 

My understanding of limp mode is when the transmission is stuck in second gear to protect the drivetrain. It only allows for 2nd and reverse. Thanks for the suggestion.