CAR APPEARS TO BE CHOKING ON THE EXHAUST, BOGS DOWN, LOOSES POWER

Allan T 10-24-2014

2 Car Pros
Re: I just had a exhaust repair shop replace the original catalytic converters, left and right, and "y" pipe while keeping the original muffler and tail pipe. The original catalytic converters were leaking from the top. My problem now appears to be that the exhaust can't seem to flow through the exhaust system after the catalytic converters heat up. This makes the car bog down and loose power. I replaced the original catalytic converters with a direct fit OEM aftermarket replacements. The replacement catalytic converters apparently came with no ports for the oxygen sensors, so the exhaust shop had to port the pipe and weld a threaded female for each oxygen sensor, one for each side. Also, the after market direct fit replacement catalytic converters did not line up correctly. The retaining collars would not fit this application, so the exhaust repair shop cut off the flared pipe ends on both the old and new catalytic converters, removed the retaining collars from each, then placed the old retaining collars on fabricated cut and flared new pipe ends to bolt up to the exhaust manifolds, then lined up the parts: new catalytic converters and "y" pipe, then welded the flared pieces to the catalytic converter pipes and bolted the rest together. What would cause this to happen? Can a oxygen sensor malfunction cause this? Can the catalytic converters cause this to occur? What is happening? What could have happened? The car runs ok from being cold, but after it warms up is when it may appear that the engine can't clear exhaust fast enough, bogs down, looses power, like its choking. At high speeds, the engine appears to be choking on the exhaust and can not accelerate. The original catalytic converters were configured with a baffle chamber that housed the oxygen sensors. The direct fit OEM aftermarket replacement does not have this configuration. What is causing this to happen? What do I have to do to correct this problem?