1992 Toyota Camry Engine erratic

They told me that the #1 cylinder has a bad valve,

How did they determine this? Is it by compression check or cylinder leakage test.

Engine misfiring can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

They said they put a diagnostic machine which told them there was an exhaust problem in the #1 cylinder. They showed me how they thought the spark was erratic in that cylinder by putting a screwdriver in the plug wire and watching the spark. I couldn't really tell by watching.

They didn't mention anything about a compression check.

I checked the plugs last week (6 months old) and they looked perfect. It runs pretty smooth on the freeway. Going up hills under 30MPH causes some missing, especially if I turn on the A/C.

Follow up with the rest of the items mentioned earlier and comeback with some results.

I'm looking for someone who will be more of a detective. Do you have any comment on what I was told by the mechanic I went to?

I mentioned some behaviors that should give an experienced mechanic some clues to narrow the likely problem down, without having to do tests on everything you listed.

Can you give me some more specific things to check? For instance, if the the coil is weak, would the plugs look perfect? If I have bad gas, would the problem have presented itself 6 months ago, and then worsened in the past month or so? Etc..

Thanks!
Robert

How did they know there's a problem with cylinder no.1 -What kind of checks did they performed to come into conclusion with no.1 cylinder.

It's my opinion that the mechanic was way off the mark and was just trying to make a quick buck. I spent a few hours troubleshooting and checking sensors yesterday. There is no real consistent behavior pattern I can discern. I'm at the point where I'm ready to take it to the Toyota dealer tomorrow, as realiability continues to deteriorate rapidly. This evening I was unable to get it to start. Hopefully, tomorrow it will, saving me a tow charge. Unless you can come up with something ingenious, we're going to have to call this quits.

Robert

My Camry wouldn't start this morning. A few hours later it again failed to start. I then checked for spark by pulling a plug wire and looking for spark while I cranked the engine. Surprisingly it started right up. I decided to drive to the Toyota dealer while I had the chance. On the way I detoured to Auto Zone with a hunch that had been brewing. For $40 I purchased an ignition coil and replaced the old one with it. Everything runs perfect now, like a brand new car. I courteously let the mechanic that misdiagnosed the problem know what the result was. He told me his machine cost $4000.

I belive it is also be fair to request that my $20 deposit to 2carpros.com be returned. I was hopeful that the clues I shared with you would have been sufficient for you to at least suspect the coil.

Thank you!
Robert

I belive it is also be fair to request that my $20 deposit to 2carpros.com be returned. I was hopeful that the clues I shared with you would have been sufficient for you to at least suspect the coil.


They told me that the #1 cylinder has a bad valve,

How did they determine this? Is it by compression check or cylinder leakage test.

If tests are performed accordingly on below you will run right into a defective coil.

Engine misfiring can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

You gave me about 10 things to check and did not specify any order, nor did you provide any clever means of performing most of these checks without taking them to a mechanic.

The only reason I tried the coil replacement was because the symptoms reminded me of those I had on a '65 Chevy Van I drove in high school, which had the same intermittent problem, which was also rectified by a new coil.

Please return the deposit!
Thank you!
Robert

In our techs defense, you were given multiple tests to narrow down the problem, yet you chose not to try any of them. The first possible cause our tech suggested was about the weak coil ---
"Engine misfiring can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire)"---
We can only go by the information you provide. We prefer not to guess based on assumptions but rather on actual data gathered from your vehicle. Simple tests rule out possibilities systematically. Troubleshooting by replacing parts works sometimes, but often it doesn't. We are glad that you were able repair your car without spending $1200. We have refunded your Donation.