1996 Toyota 4Runner Oxygen Sensor

JOHNNYQUEST619

MEMBER
1996 TOYOTA 4RUNNER
4 CYL
2WD
MANUAL
8,000 MILES

This engine has 8000 miles on a rebuilt motor. I replaced the Oxygen Sensor and the Check engine light still comes on. I hooked up the diagnostics to the car and was gettiing error code 171 and 3 cylinders are mis-firing. Replaced the plugs, cap, and rotor. The problem still persist.

At idle the engine sputters and at freeway speeds it seems to be fine.

what could be the problem?

3 Replies

MASTERTECHTIM

MECHANIC
4,749 POSTS

I would start by checking for a vacuum leak at the intake manifold area. Do this by sprating carb cleaner at the intake and listen for change in rpm, then repair the leak. Also you can do a compression test on 3 cyl and make sure its not a valve sticking. Let us know

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Sunday, March 2nd, 2008 AT 11:35 AM

JOHNNYQUEST619

MEMBER
2 POSTS

Thanks for the great Tip. I checked the intake using the carb spray and the idle changed. I found that the mechanic broke the gasket when putting the engine together. We replaced the gasket and the check engine light went off and there was no need to purchase the O2 Synsor. The engine had been running the the intake leak for a year. Could the leak cause damae to the engine?

This site is great, if I was directed here first I would have saved a couple of hundred $$$.

Thanks again.

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Friday, March 28th, 2008 AT 12:57 PM

MASTERTECHTIM