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Help!! All Issues Great and Small...

734 views 6 replies 5 participants last post by  Luckymac 
#1 ·
Hey guys so I bought a 1991 YJ Wrangler, - 5 speed manual 4 cyl, and I love it except it's having a major issue (and I have a few misc questions).

The big one: for the past couple weeks, while I'm driving along (going up hill, downhill, or flat ground) once in a while my car will start to buck and shake violently as if it's in the wrong gear (picture trying to shift into fifth from second), and the only way to fix it is to pull over for a second or downshift.

I can't afford a mechanic right now so I'd really really appreciate any and all help I could get for things I could try on my own.

Other issues / questions: the back windows of my soft top got destroyed apparently (bought it that way) so I have no back windows. It's a smittybuilt softtop, but I haven't been able to find replacement back windows anywhere and I think I'll have to get a whole replacement soft top.

Final question: there is a little silver switch on my dash with no indication of what it does, and it goes left to right. And idea what this switch is used for?

Any and all help is greatly appreciated!!! Thanks for reading!
 
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#2 ·
The big one: for the past couple weeks, while I'm driving along (going up hill, downhill, or flat ground) once in a while my car will start to buck and shake violently as if it's in the wrong gear (picture trying to shift into fifth from second), and the only way to fix it is to pull over for a second or downshift.
Those can be really hard to nail down. Could be fuel, could be spark, could be something in the trans, or clutch is worn. Do it ever feel like the trans is slipping when you launch? Does the shifter move freely between gears when shifting? Are you getting the MIL/check engine lamp at all? Check fuel pressure at the rail. Should be 30+ psi at idle

Other issues / questions: the back windows of my soft top got destroyed apparently (bought it that way) so I have no back windows. It's a smittybuilt softtop, but I haven't been able to find replacement back windows anywhere and I think I'll have to get a whole replacement soft top.
Try emailing or calling Smitty directly. They have a spot in the vendor section here. There are also reps that chime in here from time to time. They can tell you what is available.

Final question: there is a little silver switch on my dash with no indication of what it does, and it goes left to right. And idea what this switch is used for?
Sounds like something a previous owner probably added. Pictures? Could have been for auxiliary lights. A fan? Locker?
 
#3 ·
The big one: for the past couple weeks, while I'm driving along (going up hill, downhill, or flat ground) once in a while my car will start to buck and shake violently as if it's in the wrong gear (picture trying to shift into fifth from second), and the only way to fix it is to pull over for a second or downshift.
Those can be really hard to nail down. Could be fuel, could be spark, could be something in the trans, or clutch is worn. Do it ever feel like the trans is slipping when you launch? Does the shifter move freely between gears when shifting? Are you getting the MIL/check engine lamp at all? Check fuel pressure at the rail. Should be 30+ psi at idle

Other issues / questions: the back windows of my soft top got destroyed apparently (bought it that way) so I have no back windows. It's a smittybuilt softtop, but I haven't been able to find replacement back windows anywhere and I think I'll have to get a whole replacement soft top.
Try emailing or calling Smitty directly. They have a spot in the vendor section here. There are also reps that chime in here from time to time. They can tell you what is available.

Final question: there is a little silver switch on my dash with no indication of what it does, and it goes left to right. And idea what this switch is used for?
Sounds like something a previous owner probably added. Pictures? Could have been for auxiliary lights. A fan? Locker?

So as for the shifting, actually it's pretty tough to shift to first or second gears, this just started a couple months ago.

How would I know if the trans is slipping? This is my first manual car so I'm new to all this. No check engine light, although it did turn on for a day a few months ago.

Could it have anything to do with the oil? I never got a professional oil change I just put in more basic oil, could the oil filter be causing any of this?

One other thing that's been happening is that I hear a pretty loud hissing sound coming from somewhere under the hood. Guy at advanced auto parts said this was probably a vacuum leak. Could that be causing the bucking problem?
 
#4 ·
It would be a good idea to check the trans oil level. It should be even with the fill hole. Take note if it is lower than that, and how much lower. This will give you an important clue in case you have real problems in the trans.
Once you have checked and noted the level, change the trans oil . It may start shifting better with just new, full lube.

Trans slipping is when the engine will rev up without the vehicle speeding up. If you give it gas and start to lightly depress the clutch and you feel the engine start to speed up as the clutch starts to unclamp, that's what a slipping clutch will feel like.

You should use the "key trick" to read your engine codes and see what that check engine light was. It may be an important clue if it was saved.

The engine oil and oil filter will not cause your bucking.
You should, however, change your oil and filter since it hasn't been done by you yet.

You need to find that vacuum leak...it could very well be the cause of that bucking.
 
#5 ·
+1 on that vacuum leak. That will cause you to run lean. When under load, you'll be more likely to have knock.

Another +1 for everything DRED said. Check out that trans oil.
 
#6 ·
You say this is your first manual shift car, not saying you are, but it may be that you are not keeping the RPMs high enough on that 4 cylinder engine and that along with a Vac leak will make you so low on power that the car will buck and not pull, run, right.
 
#7 ·
If you go to a mechanic and ask for an estimate to fix what's wrong, he will most likely drive the car around the block and give you an idea of what needs fix. He will know if your clutch needs work and what the hissing noise is if he opens your hood.

It's unlikely he will charge you for just taking a look-see. If he takes it into the shop for any diagnostic work, be prepared to pay.

Good Luck, L.M.
 
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