2000 Toyota Corolla | Misfire codes, Tune Up Needs

[Globalksp]

Originally Posted By: Tegger
Originally Posted By: Globalksp
what else could be causing the "grossly" erratic variation in crankshaft slow down / speed up cycles? Where should I start looking

You'd already been given a few areas to check, earlier in this thread. If you're posting from a telephone, you likely missed those replies. Telephones are for making telephone calls, not for learning how to fix cars.

Some possible causes of "misfires":
- intake air-leaks
- EGR passages clogged
- poor compression (which could itself have several causes)
- faulty injectors
- damaged electrical wiring
- fouled/damaged plug(s)
- weak coil(s)

There's no "magic bullet" solution. The order you would check would be to investigate the easiest stuff first.

Mandatory tools would include a proper scan-tool, and a vacuum gauge.


Thanks for the hand holding, Tegger. And I like the sass. I have been away from my computer as I'm currently traveling. And yes, I do agree with you that the laptop is the way to go when learning to fix cars.

 

[Globalksp]

Originally Posted By: Tegger
Originally Posted By: Vikas
Computer also "knows" when the cylinder is "NOT" firing. it tells you that by blinking the CEL.

There's that misunderstanding again. Not even a blinking MIL necessarily means an ignition problem.

A blinking MIL just means that the variation in crankshaft speedups is great enough for the computer to decide that raw gas is being dumped into the cat, causing the cat to suffer damage. It still does NOT tell you which component is responsible!

It is very unfortunate that the SAE chose to call P03xx codes "misfire" codes. Every time folks hear the word "fire", they think "spark", which is misleading in the extreme. It might have been better to call them "inconsistent crankshaft impulse" codes instead.

A blinking MIL can be caused by such things as lean-misfires due to EGR clogging, or poor compression due to burned or misadjusted valves. And, in my limited experience, a blinking MIL accompanied by a P0300 can also be due to an failing ignition control module.


Again, thanks for sharing your knowledge. As far as I know, the MIL has not and is not blinking. I'll have more time to investigate things later in the month / early February. Plenty of time to read up and actually heed the advice given, instead of choosing to heed some of it. Thanks for the patience, all.