The ECM will take a few miles to re-learn the proper parameters, but this should happen within a 100 miles or so.
I would suggest that the shop that "fixed" it should hook up a scan tool to measure the parameters of all the sensors, to make sure thay are within limits. They should also measure exhaust backpressure to rule out a clogged CAT.
They should also check fuel pressure and compression and spark to isolate the problem between sensors and mechanical.
I would insist they do this at reduced cost since they have not fixed the problem.
Thursday, June 19th, 2008 AT 7:50 AM