I'm pulling onto 101 South this morning for the daily commute and begin to accelerate to a higher speed (not highway speed -- you just don't got fast on 101 in the Bay Area in the moring). I'm approaching some traffic so I let off on the gas pedal only to find that I'M STUCK AT W.O.T.!

In order to slow the car, I pop it into neutral at which point the engine revs to near redline (~5200 RPM on factory tac). At that point I turn the key to off and begin coasting.

I'm planning my exit from the highway and thinking about the fact that my mechanic buddy is less than a mile away off 101 in Redwood Shores so I figure with some creative ignition and transmission work, I can roll into his garage. When I fire the car back up, it's all back to normal. When I attempt to floor it again, it sticks yet again. Same drill.

Now I'm worried.

When I approach the off ramp, I fired the car back up again and again it's normal. I'm just going to continue on to work using the back roads. I make it OK to the parking lot.

When I open the hood of the car to check the throttle linkage, everything looks OK. The air element is not touching anything on the linkage because of the spacer I added yesterday (which consequently is the only thing messed with in the last 24 hours).

Questions:
[list=1][*]WTF!! Is this a typical problem?[*]Is the throttle cable the one on the top of the linkage where the bottom one is the TV cable?[/list=1]

Concerned,

 

Haven't had this happen to a TBI car, but plenty of times on a carb. I suspect the root cause is very similar.

Either the return sping has gotten broken/distorted/worn-out or the throttle shaft bushings are so worn it allows the throttle shaft to move around and "wedge" at a funny angle. Worn out throttle shaft bushings can make for one heluva wild ride during your morning commute! Beleive me, I've had it happen and it's scary as heck. Worn throttle shaft bushings are pretty easily diagnosed. If you experience the problem, turn off the engine, immediately restart it and all's well again it's throttle shaft bushings. The engine vacuum pulling down the the throttle plates is what causes the "wedging" effect to happen when the bushings get worn. If you remove engine vacuum by shutting off the engine the throttle will immediately close again just as smooth as silk.

Beyond that would be a throttle cable that is damaged/kinked/badly worn or physical obstruction on the throtle arm or gas pedal.

 

Where are the throttle shaft bushings? Don't say, "the throttle shaft."



I guess checking the vacuum tubes from the TBI are in order.

 

manual open and close the TBI unit with the car off. See how hard it is to open and if it sticks. Over time funk and corrosion builds up in and around the throttle spring making it hard to open and close. If that is the case, pull the TBI unit and scrub the throttle screw with carb cleaner and then re-oil it with a little grease or motor oil.

 

Yep... there is a catch in the movement. I'll do this later today, Shifty.

This will be the third time I've removed the TBI unit but a necessary time if I plan on allowing my wife to drive it or my daughter to be a passenger.

Thanks gang!