intermittant misfire/hesitation under load

[harrisonfiveo]

So I have had my 02' Camry for a little over a year. Love the car, it is a 2.4L SE with a 5-speed manual. Recently it has developed this mystery misfire/hesitation under a load and at idle with the AC on. I replaced the plugs with OEM Toyota Iridiums and it seemed to clear it up for about a month, but now has come back. If I start the car and turn on the AC it will intermittantly start to miss but not only when the compressor is engaged and it does it every now and then under a load specifically in 4th or 5th gear under a load with lower RPM's (under 2000). The check engine light is not on and hasn't as much as even flashed on at any time so there must not be any hard misfire codes. I want to stop by Autozone and see if they will scan it to find any stored codes but haven't had time. I would think that if it was a coil pack that it would be a hard misfire. I'm stumped. This car is in great condition...no oil leaks, interior is near perfect (replaced a worn shift knob, and door panel pieces around the window switch). Also car has 160k miles. Any ideas will be appreciated.


BTW...how do I post a picture??

[workerant]

post pic using photobucket. There is an instruction somewhere. Search and u'll find it.

The misfire could be due to the ignition coil. Mine was '07. It misfired around 40k odo, so no warranty and I had to pay out of pocket.

[somick]

Try to check the resistance of each of the coils and see if they are the same.

Good luck,
Sam

[harrisonfiveo]

Originally Posted by semyonlibman

Try to check the resistance of each of the coils and see if they are the same.

Good luck,
Sam

Good call, I will try to do that this evening. I just hate to throw parts at it, especially when those ignition coils are about $100 each.

[BlackG5]

I have an 04 5-speed with 190k and its strange sometimes too under heavy load. it's noticeable in 3rd around 5000-5300rpm its almost like a "vtec" engagement but it doesn't act like vtec lol, its just weird, doesn't do it all the time but hesitates sorta..

I too have the low idle thing sometimes, but the computer figures it out really quick and it'll find the right idle speed. It's really only after I mash on it a bunch and come to a stop. with the a/c on it'll idle lower more often..

Only thing that bugs me now is the throw out bearing squeels like a piggy when its rainy and cold out. stock clutch, getting ready to order the ACT street

[harrisonfiveo]

Well, I tested each ignition coil with my ohm meter and found 2 of them had really high resistance. I have two ordered from the local toyota dealership (didn't want to mess with aftermarket). So hopefully I will find out if that fixes it this weekend.

[workerant]

Are you sure you can test ignition coil using ohm meter? Isn't the coil using inductance? Or did you mean DMM (Digital Multi Meter) and you did test the inductance?

Anyway, I think now you are fixing the correct part. Your old plugs might still be good too.

[harrisonfiveo]

Replaced coils #1 and #2 and problem solved. Still baffles me that the misfire never set off the check engine light....

[workerant]

^ in my '07 it took awhile.. like a whole month it would happen like 3 times and i drive it every day. Finally it was bad enough that it throw a code. At first I thought it was just bad gas.

[Bub1958]

Originally Posted by harrisonfiveo

Replaced coils #1 and #2 and problem solved. Still baffles me that the misfire never set off the check engine light....

Don't be baffled. Despite what many mechanics may tell you, I've discovered that coils that aren't performing properly because they are going bad will cause a misfire and even a stall. It took me an entire year to get an engineer to explain to me why that happens and why it won't throw a code, but I changed all the coils in the car and the problem went right away.

Now it seems I may have the problem in the 2003 Camry, but the miss is only evident between 60 and 70 mph under light load. No CEL but I'm thinking it's one or more coils. They're original and the mileage is approaching 150K.