Shuddering 1500-2000 rpms
#1
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Year: 1991
Model: Cherokee
Engine: I6 H.O, 99 manifold, APN header, neon injectors, cowl intake, screamin demon ignition system
Shuddering 1500-2000 rpms
Okay, First off i have a 1991 with a new motor that hasbeen in the truck for a year and a half. i have had this problem for probably a year and its never gotten worse just has always been there. no matter if it is in neutral, drive, park, or reverse it does it. what it is doing is hard to explain but its almost like a rattle but its not. the whole rig including the motor and exhaust shudders when i get up to 1500 rpms till i reach 200 then it goes away. of course i have checked all the self explanatory stuff but i did have somebody hit the throttle and bring the vibration up then i pulled and grabbed on stuff underneath and when pressure was applied downward on the fursthest point back of the transfercase it went away! now i thought it would be my tranny mount so i replaced it with a daystar poly one to match my brown dog poly motor mounts. so my question is what could be causing this? also i have removed each bolt on the flex plate and reinstalled with loctite just to be sure.
Thank you
Thank you
#3
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Year: 1991
Model: Cherokee
Engine: I6 H.O, 99 manifold, APN header, neon injectors, cowl intake, screamin demon ignition system
#4
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Year: 1988
Model: Cherokee
Engine: 4.0
I don't usually reply to halfassed shinglish run-on sentences, but I did anyway and offered a real diagnosis tip to try to help you. I added a bit of humor so that those who attempted to read your mishmash might actually gain something from it if only it were a cheap laugh.
GIGO
GIGO
#5
it sounds like it could be a motor mount, have someone put it in drive and while pushing brake apply gas to put a load on engine, then do it in reverse, if the engine moves way more going one way than the other then you have a motor mount issue, could also be the harmonic pulley like mentioned above.
#6
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Year: 2000
Model: Cherokee
Engine: 4.0 I6
Have you checked motor and trans and crossmember bolts are tight?
If you don't want to be made fun of, try using punctuation.
I thought the reply was funny.
If you don't want to be made fun of, try using punctuation.
I thought the reply was funny.
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#8
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Year: 1991
Model: Cherokee
Engine: I6 H.O, 99 manifold, APN header, neon injectors, cowl intake, screamin demon ignition system
I must of forgot that I was typing a semester final paper. I could of swore I was on an internet forum asking a question? Instead I get somebody telling me how I asked the question wrong.. thanks for your input though, but I've already checked those.
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Year: 1996
Model: Cherokee
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Exactly! You're on a forum, where people have to be able to understand what you are typing. Long run on sentences, besides being annoying to read, can be extremely difficult to understand. Nobody here would consider themselves Grammar Police, but writing your question, so that it is easier to read, will go a long way to getting answers that you might find useful to your situation.
#10
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Year: 1988
Model: Cherokee
Engine: 4.0
Hopefully your semester final paper will contain proper punctuation, spelling, and good sentence structure. Unlike what you have written in all of your posts in this thread. There is a very good reason why schools make students write a lot. What do you suppose that reason is?
When you care enough to send your very best, you do. When you don't, you don't.
#11
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Year: 1988
Model: Cherokee
Engine: 4.0
The harmonic balancer looks like this...
It may not be the problem you are having, but it is a definite possibility. When mine started failing, it caused vibes at a certain RPM.
It may not be the problem you are having, but it is a definite possibility. When mine started failing, it caused vibes at a certain RPM.
#12
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Year: 1991
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Engine: I6 H.O, 99 manifold, APN header, neon injectors, cowl intake, screamin demon ignition system
Anyway to tell when it's shot? By looking at it or certain signs? Or is it best to just replace it?
#13
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Year: 1988
Model: Cherokee
Engine: 4.0
It is on the crankshaft, and it is what drives the serpentine belt. Get a flashlight and look to see if the rubber strip is good condition. Look for splits/cracks and for the rubber oozing out of the rings it is sandwiched in between.
It may not be the problem you are having, but it could be.
#14
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Year: 1991
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Engine: I6 H.O, 99 manifold, APN header, neon injectors, cowl intake, screamin demon ignition system
Yes. It is a 3 part pulley, an outer metal ring, an inner metal ring and a strip of rubber in between them. The rubber breaks down from the stress and heat of running and then the rubber strip can break, causing an imbalance. It can fail catastrophically too, and can take out a bunch of stuff along with it.
It is on the crankshaft, and it is what drives the serpentine belt. Get a flashlight and look to see if the rubber strip is good condition. Look for splits/cracks and for the rubber oozing out of the rings it is sandwiched in between.
It may not be the problem you are having, but it could be.
#15
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Year: 1988
Model: Cherokee
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Mine was a bit worse than that, but not much. Maybe some of the other members will chime in about it? They cost about $40, and your wallet thickness will decide whether or not you should replace it.
Poly bushings and engine mounts are super stiff and will transmit vibes much more readily than rubber ones will.
I hope you can get it fixed, but don't skimp on your studies. You won't be affording too many fancy upgrades while digging ditches for a living.
Poly bushings and engine mounts are super stiff and will transmit vibes much more readily than rubber ones will.
I hope you can get it fixed, but don't skimp on your studies. You won't be affording too many fancy upgrades while digging ditches for a living.