2000 Bonneville. Car/transmission function well. Mileage has dropped from about 27 mpg to about 20 mpg over last year or so.

Any one have any thoughts about my spending $1000 more or less to prevent some future problem that'* currently not obvious other than the Service Engine Light?

Who told you it was a torque convertor problem?

DTC P0480 Cooling Fan Relay 1 Control Circuit

Do you still have the code?
Many items can contribute to your poor fuel mileage, that code alone wouldn't do it.
Tell us more about your car.
Last service? oil, spark plugs, air filter etc.

Please read the Forum descriptions, and please don't post mechanical problems in General Chat.

Moving to the proper section.

Car has been serviced regularly, always by the GM Pontiac dealer. The dealer told me the engine light relates to the transmission and estimated $1000 to fix.

Mechanic at combination mechanic and body shop scanned computer (?) while doing body work and told me that the issue is a torque converter interlock issue. He was hazy about the code, so he obviously must have grabbed the wrong code when I asked. His verbal statement was generally consistent with the dealer'* statement. However, I'm a novice about these things.

I have always trusted the dealer, assuming I was paying a higher price for quality. However, the dealer blew a front brake job, leaving me with pulsating brakes at 60-70 miph. Then he blew the installation of a GM remanufactured transmission on my wife'* '95 firebird by leaving it leaking fluid. I just barely got it back to the shop.

So I don't have anyone I trust. A transmission place recommended by the mechanic wants me to leave car with them for a day. I'm concerned about leaving the car with a transmission place I know nothing about.

Your thoughts greatly appreciated.

Take the car over to one of the parts chain stores like Advanced Auto and get a free code check.

Let us know what that code is. Also, take the car on the highway, after it has warmed up, and let us know what your RPMs are at 55-60 MPH.

RPMs at 55-60 MPH vary between 1900 and 2100.

I'm still working on error code. Hope to have it next week.

Your RPMs sound high for that speed. It sounds as if you may not be going into overdrive and/or lockup. Drive the car somewhere where you can safely keep an eye on the tach, and get the car up to about 45. Then increase the speed a little at a time, then hold it steady there. Right around 47 MPH, the RPMs should drop.

Thanks,

I'll try it.