Questions and Answers

Toyota Tercel Popping Out Spark Plugs Q. About three weeks ago me and my 1997 Toyota Tercel were going to work when something went boom and my car started chugging. I opened the hood to find my spark plug, still in the wire, laying on my engine. The plug itself had all of its treads so it didn't look stripped. I put another plug back into it and headed home, chugging all the way.

Had a friend run a diagnostic and it came up saying Cylinder one misfired. He cleared the message and ran it again and it was fine. I ran the car for about three days with no problem, then one morning the plug misfired again but did not come out of the engine. Had him come over and Cylinder one misfired again.

The message was cleared and then it happened again. What should I start replacing to solve this problem?

Thanks,
Steven

A. If the spark plug was installed and tightened to the proper torque, 14 foot pounds, the spark plug should not come out. I have seen guys who put some types of "Never Seize" on spark plug threads which is not a good idea. That is the only way I can see a spark plug working it's way out of a cylinder head.

I would make sure the threads of the cylinder head and spark plugs are clean and dry. Then, with a torque wrench, tighten them to 14 foot pounds and I think you'll find the spark plug will no longer pop out of the head.