QDear Tom and Ray:

Is my mechanic a crook? I had the timing belt replaced on my 1990 Mitsubishi Eclipse. The morning after I drove it home from the mechanic, I noticed oil pouring out of the car. It turns out that the rear main seal was blown. Is it possible that my mechanic did this while replacing the timing belt, or is it just a coincidence? He says he was working on the opposite side of the engine, and there was no way he could have done this. But I've heard that if you tap too hard on the front, you can blow the rear seal. What's your opinion?

-- Jennifer

ATOM: It sounds like just an unhappy coincidence, Jennifer. There's really no way he could have blown your rear main seal by changing the timing belt.

RAY: He's right that they're on opposite sides of the engine. The only thing that links the two is the crankshaft, and it's not supposed to move longitudinally more than a fraction of a millimeter. If it does, and tapping it in front pushes out the rear main seal, then your engine was in terrible shape to begin with (not an impossibility on an 11-year-old car).

Dear Tom and Ray:

Can one have too hot an ignition spark? There are several aftermarket ignition systems available for older car engines, most claiming to produce more voltage than stock systems. But can you overdo it?

-- Clyde

RAY: It will wear out your spark plugs faster. It'll also wear out the other parts of the secondary ignition system faster -- the plug wires, rotor, distributor, etc. So you'll be buying new ignition parts more often, but it won't do any permanent damage to your engine.

TOM: The idea is that a higher-voltage (or "hotter") spark will do a better job of burning all of the fuel in the cylinders. And technically, that's true. But in reality, it only really helps if you suffer from excessive turbulence in your combustion chambers.

Dear Tom and Ray:

I have a '93 Toyota Camry Wagon. Lately, I have been having trouble with the accelerator pedal. It will stick sometimes and be hard to depress. When a traffic light turns green, I sometimes have to jab at the pedal to get it unstuck. I have tried lubricating around the pedal and lubricating the part of the cable that's exposed under the hood. What gives?

-- Wendell

RAY: I think the problem is in the throttle body. Sometimes, carbon builds up on the throttle plate or on the walls around it. And that can make the plate stick in the closed position. In fact, most manufacturers now recommend that you have the throttle plate cleaned on a regular basis. So that would be the first thing to look for.

TOM: The other possibility is that sometimes, on cars with a lot of miles on them, the throttle plate actually wears a groove in its aluminum housing. Then the plate gets stuck in that groove. In that case, you can try adjusting it, but if that doesn't work, you'll need a whole new throttle body, and that's mucho dinero.

RAY: In my vast (or at least half-vast) experience with Toyota Camrys, I'd have to say that it's not likely to be the accelerator cable. We almost never have to replace accelerator cables on Camrys for this problem. And in any case, you're never supposed to lubricate that cable. The grease you apply just ends up attracting MORE dirt and makes the cable MORE likely to stick.

TOM: So take it in to your mechanic, Wendell. Ask him to check the throttle plate to see if it's moving freely. If it's not, hope that it's just built-up carbon, or cash might be moving freely out of your pocket very soon.

Got a question about cars? Write to Click and Clack in care of The Post or e-mail them by visiting the Car Talk section of the Cars.com Web site.(c)2001 by Tom and Ray Magliozzi

and Doug Berman