Q: Car runs bad. Suspect O2 sensor at least. Had exhaust leak due to cracked manifold. Guy welded the manifold and now it runs

asked by on December 30, 2016

Bad. He said the cat was empty. I suspect that the cat insides caused a clog which in turn increased back pressure which caused other exhaust leaks. It does seem that there is ample exhaust out the tail pipe. ?? So I don't have much money and am looking to get back on the road. At present it takes about two miles to get the truck up to 45 mph. Low rpms only. Running very rich. Thought of changing the O2 sensor next to the repaired manifold but hard to get a wrench on it. Odd that the cat ran much worse immediately after the repair. Scan just show multiple engine misfire but I've got an old computer in the car and it does a few goofy things with the dashboard lights etc. I took it to Midas and they wanted $2100. Can't do that. What would you do?

My car has 300000 miles.
My car has an automatic transmission.

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