QuestionTed thanks for the advise. I have replaced both coil packs from Toyota and guess what...I am still getting P0301. I reckon, bend over go to the Toyota dealership and let them fix a $10.00 problem for a couple hundred dollars.
I'm stuck.
Jerry
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Followup To
Question -
Ted, I know that you are getting tired of this question, but here is what I have done and the results; 1998 Toyota Corolla
P0300 and P0301 Code
Changed plugs with factory plugs
Clear codes...codes come back
Changed wires with factory wires
Clear codes...codes come back
Check compression...all cyls within 5 lbs.
Clear codes...codes came back
#1 and #3 injector switched
Codes cleared...Now P0301 only
Replaced o-rings and boots
P0301 code again!!
Switched #1 and 3 sparkplug
P0301 code again!!
Check fuel pressure...within factory specs
Change air filter ...same results
Short of going to the dealer and bending over, which direction should I go in next? I believe that I have the knowledge and tools to troubleshoot...just need a push.
Thanks for your help.
Jerry
Answer -
The PO300 code is kind of a generic code that tells you that, yes there is a misfire, the 301 is directly related to the #1 cylinder, it's not he injectors or the misfire would have moved to the #3 cylinder after switching, the misfire is still persistently on #1.
As you probably know there is no distributor but there are two coils, each firing two cylinders, it is possible that one of these coils is giving you the problem, locate the one that is marked with the #1 and replace it, I don't remember how they are paired, it may be 1 and 3 or 1 and 4 , regardless, try replacing the one that includes the #1.
AnswerI have just about exhausted my knowledge base on this one, before I go on let me explain to you how a misfire code is logged to turn the check engine light on.
As the engine is running the crankshaft speeds up and slows down on each revolution per cylinder and if everything is ok the computer looks at this via the crank angle sensor and there is no problem,as long as all of them are doing the same thing, when the computer sees a deviation from this such as a cylinder that is not speeding up/slowing down at the same rate as the rest of them it will interpret this a a misfire and turn the check engine light on
This can also be caused by a vibration, there have been cases where a vibration has caused this and not a misfire, make sure that there is no excessive vibration caused by either a bad motor mount or even out of balance wheels that vibrate at higher speeds, this may sound a little strange but it is possible especially since the engine doesn't seem to be the cause.
