Hello, I have an older 99 Honda odyssey van, my mechanic cant find a problem because when it idles - its fine. However, I'm cruising or on highway at 45-55mph the engine misfires.Thanks in advance for any help.
make sure fuel pressure is within spec and get a real mechanic
Since then the fuel pump has been changed.
well if you just replace stuff without testing anything you'll never know what the problem is.
See the misfire article in our FAQ.
the fuel pump was replaced, not as a blind effort to find the root cause, but because a later issue happened that the pump would shut off intermittently - and that fixed it.
If you believe the misfire article in the FAQ is of help, please specify the title or a link since there are several with the word 'misfire' in it. BTW the misfire FAQ's i've already read have the misfire happening at idle, my circumstance is that the misfire DOES NOT happen at idle, but at highway speeds, intermittently.
Thank you in advance for any comments.
the fuel pump was replaced, not as a blind effort to find the root cause
well maybe the pump doesn't shut off, but you still haven't confirmed you have good fuel pressure.
You can do things once thoroughly, or you can make assumptions and do them twice.
please specify the title or a link since there are several with the word 'misfire' in it.
I'm not sure where you're looking. The FAQ has precisely one article with the word "misfire" in the title.
BTW the misfire FAQ's i've already read
so what troubleshooting did you try, and what were the results?