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Annoying Powerband

Super mud

NAXJA Forum User
Location
Bel Air Maryland
Hey I got a 91 I6 auto mj with 200k that doesn't make good power till 3000rpm. I've had this noticeable powerband in a 87 and 89 also. I was wondering if it was common on older I6s. The 87 it went away and makes great torque now but the 91 still sucks after 5000k miles of DD. Other than that it runs fine, no light and had a tune up right before it was parked for 7 years. Maybe check the tps. Idk on the cat. Thanks.
 
If it is different when cold and after it reaches operating temperature I'd check sensors. If it is the same hot and cold it may just be the nature of the beast. In later models (HO) they moved the torque band higher (cam) and won a few more horses.

I have noticed when the O2 sensor starts to go, at peak torque on a hot engine, the motor (RPM) kind of dies (gets sluggish) and the motor dies again (really sluggish or falls on it's face altogether) up near redline.
 
Just getting back to wanting to address this problem still. Now the powerband has moved up to 3500 rpms. I noticed it has more power when cold and 8mud talked about the sensors. I had looked at the IAT a while ago to see if it was covered in sludge like my 87 but it was fine. Maybe test CTS and O2 even though it doesn't have a code? I don't have much knowledge about what the OBDI does.
 
If you are running stock size tires, its time for a compression test.
 
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