CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

94 TBird tranny surge

First and foremost, I’m car illiterate. I can barely change tires. So the following information is/was obtained by using google.

My car (1994 TBird, LX) has an intermittent problem where the rpm’s surge while I’m cruising down the freeway. I’ve noticed that it happens more often on an incline, and it also happens more during rush hour when I have to frequently slow down and the accelerate again.

If I had to guess, I think it’s the TCC Solenoid that’s the issue. Would replacing this likely solve the problem? Or would I be better served having my mechanic unplug it? My car is giving error codes to replace the camshaft position sensor (related?), and while important, I need to address the rpm issue first as it’s getting progressively worse. Tranny fluid is clean, although I’ve only owned the car for 2 months so I don’t know when it was last replaced.

Any thoughts? I can’t afford a huge repair, but I have a certified mechanic who’s always done right by me, but he’s not the best at diagnosis. I’d feel better if I could whittle down the issues and then just tell him what to fix.

Any input is appreciated. Thanks folks!

The torque converter clutch on any Ford unlocks when the brake lights come on. You can test this out by lightly tappig the brake pedal while maintaing constant throttle position—the tach should show a few hundred RPM increase. A poorly adjusted brake light switch or even burned out brake light bulbs can be the simplest cause for this.

If you have an error code related to the camshaft position sensor (there is no such code as “replace camshaft position sensor”, only codes for signal or circuit), I would track down and correct that issue first. The camshaft position sensor affects fuel delivery and, if it is not delivering the correct signal, will cause surging, which will get progressively worse and lead to stalling and failure to start. You stated that you believe it to be a transmission problem, but you also said you are car-illiterate. Many, many people mistake engine driveability problems for transmission problems, so I would start with correcting the cause of the camshaft position sensor trouble code. It may or may not be the sensor itself, but simple tests can be done to narrow it down to the sensor, circuit, or signal. If you have the 3.8L, you may also want to check the drive teeth on the synchronizer. Worn teeth can cause erratic behavior and could also interfere with proper oil pump operation, possibly wiping out the engine.