Need help troubleshooting other car

[davidkimchee]

Hello

Since theres so many knowledgeable mechanics on this forum I thought Id ask for some help.

My dads camry started acting up. 1997 V6 150K miles.

P0301 code cylinder 1 misfire

So far ive done the following to no avail
Changed plugs
Changed wires
Changed coil
Changed injector
Cleaned MAF sensor

The problem is the exact same. I can clear the code and the car will run perfectly fine. Then starts to shudder and throws the code. Odd thing is this can be anywhere from 2 days of trouble free driving to 5 minutes.

Once the CEL is on the car no longer stumbles.

Anything else you guys suggest I check? As far as I know the car has original O2 sensors and cat.

 

[Larry Bastanza]

You mentioned "coil" as in "single" coil. Do you mean the #1 coil. I am not that familiar with these, but if it only has one coil it has a distributor right? Did you change and/or inspect the distributor cap??

My 1998 Accord has a distributor cap, not sure it Toyota followed suit.

Just a thought.

HTH,
LarryB

 

[davidkimchee]

Hey Larry
The car has 3 coils. Cylinder 1 and 4 share the same coil. I actually changed all three figuring might as well do some preventative maintanence while I was at it.

 

[zahntech]

This toyota motor has had major Sludge issues ...have you checked the compression/leak down in that cyl?....you have thrown a lot of parts at this car with no results, I would start looking at the condition of the motor mechanically...when the Check Engine Lamp comes on the car goes into a "Fail Safe" mode and it runs a richer mixture so this may explain why it runs better after the lamp is on or it could just be coincidence...JZ

 

[davidkimchee]

After I gave up on fixing the car my father took it in to his mechanic. Its been there twice so far and is going back again today. He doesnt seem to be getting anywhere with this problem.

I dont really trust this mechanic but hes done our work for years and has always been reasonable.

He claims to have tested compression and also decided to change the plugs again.


I also forgot to mention that I ran an engine flush treatment and also ran half a bottle of seafoam into the intake thinking it might alleviate some crud.
Probably didnt do any good but was worth a shot.

It seems the problem may be electrical. What could go bad to prevent the coil from firing properly and only for 1 cylinder?

 

[zahntech]

That cyl gets its spark from the wire that runs up to the coil on the front valve cover,,but if you have replaced the wire and the coil, you mosty likely do not have a problem there,,,if you do not have a problem with compression/leak down in that Cyl..than you will need to look for the more bazare sorts of problems, like broken wires in wire harnesses and so on...

can you make the car misfire in the shop?...if you can that it shouldnt be difficult to find out what you are missing....the cyl needs 3 things to function 1: air/fuel 2:compression 3:spark....when it is missing you do not have one of these things in the proper level..JZ