Hello all
Here are the basics. I have a 94 Jeep Cherokee with manual transmission. It has a straight 6 in it. It has 153,000 miles on it. It has recently had the TPS and CPS replaced.
I have been having a serious issue with it – even when those things were replaced – and I am hoping (HOPING) someone can understand me.
The issue – Keep in mind if it is in neutral and you are going along or even rev the engine up – it is normal. I am driving along – in 1st, 2nd, 3rd and 4th – and now slightly 5th – it will buck like a crazed lunatic anytime the gas it barely touched – like if I press down with a toes strength, and it also happens when I lift off of the gas pedal. It also happens in gear not touching the gas at all. It just goes nuts. It literally throws you – it also does this in reverse. The cold and heat do not matter and it has gotten worse over time. Now, to top it off, while I am driving along at a “held” speed you can feel it hesitating as we are going along – little skips, sometimes larger than others. Noticeable. I have no clue anymore – is it my slave cylinder? My clutch? My engine mounts are fine – but what is up with it doing this bucking thing when I tap and lift off the gas as lightly as I do? Why does it throw me to and fro when just switching gears – it is nuts. Any help, as you can obviously see, would be greatly appreciated. Thanks everyone.

 

It sounds like you need an exorcist more than a mechanic!!

 

Sounds like its in the clutch. Thee might be grease or oil on the clutch plate causing it to slip n grab. Had an old Ford with I-6 that did the same thing.

 

I had an old cj once that the fuel pump was leaking/DUMPING fuel in to the oil and would over fill to a point that it would buck and jerk that way.

 

idk if it would do it but could it be possible that your rear main is leaking enough to get oil on your clutch disk?

 

That's what I was thinking, either that or valve cover. That's why I suggested to check the clutch.

 

Hey everyone - thanks so much for all the help this far. Here is an update. Now, to add insult to injury, just yesterday - after my original post, I left work to find another issue. I started her up, and had her in neutral - now, if I ever so lightly press the gas when it is in neutral it goes to almost stall, and then kicks back into normal mode - but it does it every time with just a light touch to the gas pedal. Ugh. I am so sick of this - I thought the clutch too, but maybe gas - too many things to know, but I was hoping someone out ther may have had experienced similar. Keep the help coming - I appreciate it soooo much!

 

I know it isn't the fuel pump - thats new, but maybe the lines??

 

Yeah! Tell me about it - or I need really good car insurance then decide to drive it off of a cliff.

 

Check the TPS or CPS. The TPS tells the computer how much the throttle is open so it can add fuel accordingly. And the Crankshaft Position Sensor tells the computer where the pistons are so the ignition system knows when to fire.

 

I found one! Lol

 

New aftermarket fuel pumps can be a crapshoot. Most of them are made in China with spotty quality control. Some brands (Airtex for example) have a track record of failure....
Put a fuel pressure gauge on it before you write off the pump (or regulator) as OK.

If it isn't that, do you have a vacuum leak somewhere? TPS voltage correct with a smooth increase as you open the throttle?