2 issues, low rpm & high rpm
02-12-2011, 02:52 PM
#1
2 issues, low rpm & high rpm Ok, to start these seem to be two separate issues, but I could be wrong.
#1- When leaving off idle, the car has a little sputter, like a tiny sudden loss of power but it goes away. When I am in high load situations (low rpm, high gear) like 6th at ~1700rpm, if I give it like 50% or more throttle, the car will have a sort of hiccup and just run rough until 2100rpm. Doesn't do this any other time, other than low rpm, high gear, 50%+ throttle. After ~2000rpm, never happen again no matter what rpm/gear/throttle combo.
After doing a little research and thinking, I think it would be a bad o2. My gas mileage has kind of taken a dive, so that leads me further to think it's a bad o2. Just had a plug change last week btw. Backfires are from running rich, so the o2 could just be **** and dumping fuel causing the backfires.
Correct me if I'm wrong.
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#2- At high rpm @ WOT, at 4200rpm+ the car has a vibration coming from under my ***, maybe slightly behind, all the way to redline. Doesn't do it in neutral, and doesn't seem to do it at part throttle either. If it does it then, or at lower rpms, it's too subtle to feel.
This leads to think it's driveline related, specifically the driveshaft. A couple people told me the driveshaft can come unbalanced, like when a wheel loses a wheel weight, causing the vibration. The other thing I was told it could be is play in the U joints.
Any help there? Don't really know what that one would be.
ANY HELPFUL INPUT IS WELCOME AND APPRECIATED.
#1- When leaving off idle, the car has a little sputter, like a tiny sudden loss of power but it goes away. When I am in high load situations (low rpm, high gear) like 6th at ~1700rpm, if I give it like 50% or more throttle, the car will have a sort of hiccup and just run rough until 2100rpm. Doesn't do this any other time, other than low rpm, high gear, 50%+ throttle. After ~2000rpm, never happen again no matter what rpm/gear/throttle combo.
After doing a little research and thinking, I think it would be a bad o2. My gas mileage has kind of taken a dive, so that leads me further to think it's a bad o2. Just had a plug change last week btw. Backfires are from running rich, so the o2 could just be **** and dumping fuel causing the backfires.
Correct me if I'm wrong.
-----------------------------------------------------------
#2- At high rpm @ WOT, at 4200rpm+ the car has a vibration coming from under my ***, maybe slightly behind, all the way to redline. Doesn't do it in neutral, and doesn't seem to do it at part throttle either. If it does it then, or at lower rpms, it's too subtle to feel.
This leads to think it's driveline related, specifically the driveshaft. A couple people told me the driveshaft can come unbalanced, like when a wheel loses a wheel weight, causing the vibration. The other thing I was told it could be is play in the U joints.
Any help there? Don't really know what that one would be.
ANY HELPFUL INPUT IS WELCOME AND APPRECIATED.
02-13-2011, 09:07 PM
#3
top be honest you seem to be on the right track. pull the drive shaft and have it balanced and a couple of u joints pressed in. Make sure you dont have any vacuum leaks. i found that my air check valves went bad and caused backfires and running rich. So that might be a good route to check also. But for most of our cars it may be time for 02 sensors anyway.
02-13-2011, 09:21 PM
#4
I'm going to check the driveshaft/u joints tomorrow, but I think that's what that will end up being.
The other issue is kind of puzzling, so I hope it's just the o2s. Got a friend with a scanner thing to check what the o2s are reading, so we'll see what kind of shape they are in.
The other issue is kind of puzzling, so I hope it's just the o2s. Got a friend with a scanner thing to check what the o2s are reading, so we'll see what kind of shape they are in.
