the symptoms: when car is cold (not up to operating temp) it performs as it has the last 6 years - perfectly. when the engine is warm, pressing the accelerator about a third down (where you normally would want to accelerate when starting out in first) there is stumbling and hesitation that is like there is lack of fuel. if you back off slightly then reapply the accelerator, all is good and the acceleration is normal.there is no check engine light, and there are no vacuum leaks that i have discovered- i checked all the vacuum hoses, etc. Fuel pressure is fine as well. I have not looked at the computer readout (where you turn the screw all the way in to display codes on the computer under the dash) - but i was hoping to hear from the pros! Thanks. - robbie ps - i want to say its a throttle position sensor, but that is supposed to trigger the CEL according to the manual. Thanks!
91 nissan sentra 1.6 liter 4spd problem with stumbling/etc
Oct 18, 2009
6 Replies
on 10/17/2009 11:22 PM (ET) Robbie Wilson wrote the following:
You might check for a clogged catalytic converter. I had a similar problem with my 87 Pulsar and that was my problem.
That phenomenon can be indicative of an oxygen sensor getting lazy. If you have a scan tool you can watch the oxygen sensor switching at idle and determine if it is switching too slowly. I assume the distributor cap, rotor and spark plugs are known to be good. Without diagnosis with a scan tool you're shooting in the dark. Good luck. Al
Lots of possibilities there, and with it not throwing a CEL, you'll want to go through the FSM diagnostic tree. Grab your FSM here (
formatting link
)... EDIT: Just realized you have a 91, not 94. Procedure should be the same. As Al said, I'd be checking O2 sensor, but ALSO the temp sensor (believe it or not).
Welcome back NissTech...you have been sorely missed
I've been here all along.
Just have not been replying too much,the group has been kinda dead.
Second the post that NissTech is a username I love to see- always the intelligent, easy for a layman to follow response!
NOW- the (un-obvious) solution to my sentra problem- i experienced a no-start condition on the sentra and immediately started troubleshooting the ignition system. i remembered that at some point the switch was giving intermittent trouble but it went away. I took the (pressed-together) electric portion of the keyswitch apart and cleaned the contacts and reinstalled. THEN the switch blew the 30a fuse - which let me no there was a short in the switch. So I ordered the replacement switch for 33.00 and waited. When I got it and reinstalled and put in new fuses I was rewarded with an engine that would crank and run. What I did not realize was that the engine has also been cured of the stumbling! A eureka! moment of course but it makes good sense- the CEL is not going to be triggered by someone turning the switch on and off more rapidly than you can blink, but it WILL cause the car to lose power for small amounts of time. I plan on an extended drive to confirm the fix, but I'm thinking the problem is solved (til next time!) :) Thanks to all posters, and particularly NissTech - you rock!
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required