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Discussion Starter · #1 ·
Is there any reason why putting in a new Bosch O2 sensor would cause hesitation at low RPMs? There was a little hesitation before with the old (OEM original '93 w/ 157k), but now it's worse at low RPMs. Does the ECU take a while to learn the new O2 sensor? It feels like there's a power increase starting abruptly at ~5,000rpms though. I'm going to put the old one back in for testing soon.
 

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Discussion Starter · #2 ·
After doing some reading, I think I found the problem. I can't figure out just WHY, but apparantly having a non-working alternator can cause stumbling and hesitation under load at low RPMs. I've found several other threads where others have made the connection between alternator and hesistation.

Anyone know why this happens?
 

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Jeff, did you know the alternator was bad before the sensor install or did you find it because the new sensor?

I suspect mine might be getting tired I really got to take a look at it.


Oh, and thanks for actually posting the solution to the problem in your thread. Too many times it seems we don’t get conclusions to problems in threads, just a list of things to try.
 

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i have the same hesitation/spuddering at low rpms (2500-3000). Im guessing my o2 sensor has about 286,000 miles on it because thats what the body has on it and its had 3 engines, and im sure the o2 sensor hasnt been replaced. I think i might go 2day to get the o2 sensor so ill let u know how it runs.
 

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my car actually ran better (or at least it seemed) without it connected. Maybe something was happeneing that I didn't want to happen. Anyway I reconnected it and now it's fine and I never had a C.E.L.

Here is a great connection for you. My alternator dropped while driving. The belt fell off and the car was running off the battery. I couldn't get the engine over 2000 RPM while in motion however I could rev it without problem when stopped. luckily I was 3 blocks from home when it happend. I limped it home and fixed the alternator and it ran fine....

I'm sure the alternator has a LOT to do with the engine hesitation and slugishness.

P.S. None of the wires became disconnected when the alt dropped..just the loss of the belt..........
 

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Discussion Starter · #7 ·
I replaced my O2 sensor while I was doing my clutch install. I noticed some smoke coming from the alternator area when I started the car back up to test the new clutch, but I thought it was just some transmission fluid boiliing off or something (although the smell did seem electrical).

At that time I didn't put 2 and 2 together. While testing out the clutch I noticed the stumbling/hesitation and chalked it up to the new O2 sensor. I didn't know the alternator was bad because the battery light wasn't on, but after 20 mins of driving the car died once the battery ran out of juice. At that point my friend and I put together what had happened and that the alternator was the culprit. I'm putting in a new (used) alternator Saturday and I'm hoping this will be the end of my hesitation and stumbling problems.
 

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ok seems like i have the same problem i had an actually real bad hesitation whenever i hit the gas so i changed the o2 sensor with a bosch one and it worked awsome, so maybe 2 weeks later now my car sputters at low rpm's so im like wtf, im thinking it could be my fuel filter but i havnt changed it yet, but its like its missing fuel squirts after the car gets warmed up, and going put put put and then kicked in hard and smooth around 5k like you said. my altenator seems to be fine, car doesnt die on me even though it sits somtimes for a week or two. I dont get why these cars/engines suck so bad to tune. i never had this problem with any other car. seems like you fix one thing and the damn thing wants to **** up some where else.

what about rotor caps and buttons has anyone looked into that.. couldnt carbon deposits cause the same thing? i havnt had time to check it out.
 
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