Car acts like it has a misfire under load

CHIEFSMOKES

MEMBER
2000 NISSAN MAXIMA
3.0L
V6
2WD
AUTOMATIC
175,000 MILES

Car acts like it has a misfire under load. 60 mph seems fine around town but once it is warm seems to get worse. So far I have replaced the following: fuel pump, filter, MAF. Cleaned throttle body IACV. Replaced plugs and coils, gas tank and fuel filler neck. I have a new code for temperature sensor and sender. What else could I be missing? Every time I replace something runs good for a day or two and right back to jerking bucking under load.

4 Replies

CARADIODOC

MECHANIC
33,741 POSTS

I would suggest to take a look at the injectors, you may have one that is failing.

Here are a couple guides t read that will help you figure it out:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

https://www.2carpros.com/articles/how-to-replace-a-fuel-injector

https://www.2carpros.com/articles/how-to-use-a-voltmeter

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Monday, August 12th, 2019 AT 12:26 PM

CHIEFSMOKES

MEMBER
3 POSTS

I have both my coolant temperature sensor and sender now. When I replace them I will check the injectors. I would just think that if the injectors were bad I would get a misfire code or that it would misfire whether it was cold or warm.I wouldn't think it would run fine under 50. It doesn't seem like it starts to become a problem until I'm over 50 mph. Then once it starts it just gets worse. At this point I'll try anything.

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Monday, August 12th, 2019 AT 12:56 PM

CHIEFSMOKES

MEMBER
3 POSTS

Well CARDIODOC. Not 100% sure but after throwing parts at my car for about two months I replaced the coolant temp switch and sender and my max idles well and after taking her on a pretty thorough test drive pushing her a little harder than I typically would, the coolant circuit may have been the problem. I don't want to get my hopes up because I hadn't checked the injectors yet. ( Need to get some replacement o rings first) I did check all my vac lines and my intake though and no leaks. So hopefully this is a victory. Give everyone an update in a week.

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Wednesday, August 14th, 2019 AT 4:36 PM