Toyota Corolla Camshaft problem

My check engine light came on about a week an a half ago. I went and got it checked out once at autozone and was told it was one of the engine coils. I went to a car shop and was told they couldn’t find anything wrong with it hence the check engine light wasn’t on at the time. My engine light goes on and off and i know when it about to come on because my car shakes. I brought it to someone i know that works for the dealer and i was told that it has a problem with the camshaft hoewver there is no way he would know exctly what is wrong with it. He said he would have to start from the bottom (according to him a sensor “camshaft oil control valve assembly” and work his way further if that doesn’t fix the problem. The last step would be the motor. My problem is that i do not want nor do i believe i should have to pay for every step until i figure he figures out what the problem is. I don’t want to pay any unecessary money, i want to know what is wrong and exactly what needs to get done to fix it. Any advice i would appreciate it…

What model year is your Corolla?
Does its engine have Variable Valve Timing?
If it does have VVT, it is very possible that this problem is the result of going too long between oil changes.

What can you tell us about your maintenance schedule–in terms of both odometer mileage and elapsed time?

What year Corolla is it and how many miles on it? If you can, get the exact trouble code that was read from the computer.
I have a 2009 Corolla with 80K miles. I have had recent problems with the engine running rough for a few seconds and causing the check engine light to go on. The problem was a bad coil. The symptom was unusual since the car would run perfectly for weeks at a time in between “the shakes”. I noticed that it usually happened when I was in stop and go traffic, probably because the coils get hottest then. If this sounds like what you have experienced, wait until the engine shakes again. The engine computer records the trouble code and indicates exactly which of the four coils is bad.

Usually when the check engine light goes out, it means that the condition that set the code has not been detected in the last three drive cycles. After ten drive cycles, the code is erased from the computer. The next time you get a check engine light, try to get to the AutoZone to get the code read as soon as possible.

When they read the code, ask them to give you the readout of what the code means. They should enter the code into the computer at the checkout or parts counter and give you a printout on cash register tape. The code will be at the top of the printout and will start with a P followed by 4 numbers. A typical code might be P0303.

Post that code here.

You are right to expect your mechanic to act in a business like manner. Your mechanic should run full diagnostics to determine the exact part you need before replacing any parts. But a full diagnostics takes time, it is more than just reading a code on a code reader and for that time, he deserves to be compensated. Full diagnostics usually cost about an hour of labor.

But it is also very difficult to start the diagnostics without a code first or a problem that is consistent and not intermediate like yours.

Anyway, when you get the exact code, post it here and we can then offer further advice.

The shop should check the operation of the oil control valve first. It is a very easy test, if when it is actuated, the engine does not run rough or stall the valve should be remove and inspected visually. The filter screen also needs to be inspected at that time. If both of those items are good the vvti gear will need to be replaced.

When they read the code at Autozone, did they give you the code? Tell you which coil? If so, buy a coil and replace it. It’s an easy job and you’ll save a ton of money. If the check engine light is on, the code can be read.

Good idea to post the actual diagnostics codes retrieved from ECM memory here. Best case would be a bad coil, and that would indeed cause the car to shake, and could easily occur intermittently, only when the engine was warm, etc.

You post some intriguing ideas about what services you should have to pay for, and which ones you shouldn’t. I understand you want to minimize the cost to fix this problem. But the mechanics who fix it for you have to earn a living too. They usually can’t afford to donate the time for services. No harm asking though.

Another way to look at is, say you go to the doctor for a sore throat. He does a test, and the test shows that isn’t what is causing the sore throat. It’s something else, and another test is needed. How would you feel about being presented the bill to pay for that first test?

I have noticed that you consulted a a parts store counterman and “someone who works at a dealer”. You have received a free diagnosis from each and you see what they are worth.
My advice would be to consult a real mechanic, you should expect to pay for the mechanics time to diagnose the problem. Don’t go to someone who says, well it is probably X so we will replace X and see if it fixes it.
If you don’t want to pay for diagnosis, be prepared to pay for parts and labor, lots of parts and labor and the person who is replacing those parts will keep telling you that each part was needed but you also need X, then Y and Z. If he can’t think of anything else to replace, he will tell you it is your computer.
If you let him replace your computer and you go back to him because that didn’t work, he will turn out his lights, lock his door and hide in the back room until you go away.

An intermittent coil is an excellent possibility for your symptoms, especially since the engine shakes when the problem occurs, but we need more information first.

I think Oldtimer has given you good advice. A reputable mechanic can diagnose the problem without tearing the engine apart, using well accepted diagnostic steps and basic equipment. It’ll be a whole lot faster, easier, and cheaper in the long run than guessing or getting continuous free advice… which are all just guesses unless actually checked hands-on.

And don’t go to the dealer. They often don’t want to be bothered with older vehicles (although I don’t consider yours older, dealers seem to have a pompous attitude… anything not new is old). Too much work, and the customer usually complains about the high cost.

VDC hit the nail on the head. If you have VVT…which is Toyotas flavor of Variable Valve Timing…If the control solenoid that controls the variable cam adjustment is not working properly it can cause a misfire akin to a coil going bad.

If you only get this one code referencing the VVT Solenoid and NO CYLINDER MISFIRE Codes…then I would definitely look into the VVT Control Solenoid and the VVT system in its entirety… The Solenoid very well may be working… But as another guy suggested…this could be an issue with oil change frequency. The solenoid may be operating properly…but due to a clog in the oil passages that feed and or drain from the Solenoids path…it will error out and blame the solenoid.

If there are no cylinder misfire codes that would point to a faulty ignition coil I would do an engine oil Motor flush treatment first…to see if this issue goes away. This treatment would attempt to clear or clean out the oil passageways…and this may solve your issue. This is a little bit wishful thinking however because clogs very often require manual intervention to clear up or clear out any kind of clog in a system with very narrow passageways and also with very low flow rates and pressures. OR you may actually have a faulty VVT Solenoid… Its easy to test the solenoid if you knew what you were doing.

Its kind of hard to advise you because you arent doing the work yourself…I can advise YOU…But then you need to somehow communicate my advice to a COMPETENT Mechanic…and then he or she has to take it from there. I think the guys here have the issue pretty well pegged however.
Maybe its time to copy n paste all of our advice into a document and then take it to a good Mechanic who actually CARES. That is the only way you will get this issue resolved…OTHERWISE each place you take this to…will start off Blind and only go on what the error codes tell them.

Error codes are a sort of funny thing. They are NOT meant to be taken at face value… For instance…if you cut the power wire to a certain sensor…and it has no power at all… The engine ECU will tell you that this sensor has FAILED… When in reality the power wire feeding the sensor has been CUT. So you can see how these codes are sort of “suggestive” rather than “Pinpoint” if that makes any sense to you. The same is true here with this VVT Solenoid code…it can be the solenoid itself yes…but it can also be the oil pressure FEED and or DRAIN passageway that is part of the VVT Oil flow and solenoid SYSTEM itself…