My check engine light is on?

I would be checking for a vacuum leak, if you are getting a code for 1 bank only I would be looking at that side of the inlet manifold to start with.

Mark (mhpautos)

First off, what type of transmission do you have? Does it see a lot of hard use like hauling/towing or going over mountain passes.

Second, what is the fluid level like?

Since the overdrive light is flashing that means the PCM has detected a fault in the transmission. Best bet would be to go and have the PCM scanned and get back to us with the results and we can go from there.

The reason I asked if the fluid level was ok was because low fluid levels could cause the symptoms you describe.

Remove the dipstick and check the color and smell of the transmission fluid, if it has a smell of being burnt or the color is a brownish color. With 148,000 miles of some light towing the filter and fluid could use a changing.

Change the filter and fluid. And maybe pray it ain't too late.

DAmage is being done to the converter. Probably a situation that is causing an excessive amount of fuel that is unable to be burned correctly. You do not want to drive it like this. Either get it checked out ASAP, or get the codes from the computer and I'll try to help.