Hard bucking when accelerating, cutouts at high RPM (parked on side of interstate)

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Pacman0939

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Driving home last night and my 2004 RHD TJ began acting up. Cruising along at 65mph and noticed some pretty intense bucking would start with higher throttle (first noticed it when climbing a steep grade on the interstate), letting off the skinny pedal would resolve it immediately. The issue became worse over the next 20 miles to the point I had trouble maintaining even 45mph on flat interstate. Finally, if the transmission downshifted into 3rd gear and raised the engine RPM as a result, the Jeep would sputter and lose power every couple of seconds; almost like all fuel was being cut. Pulled over and the engine idles fine, no noticeable issue. All gauges are in correct ranges. Battery connections are good. Parked it for the night and got a ride home.

I wanted to check with those of you on the forum and see what your take was. I plan on getting a ride after work and attempt to limp the 40ish miles home.

Relevant background - I have an intermittent check engine code for cylinder 1 P0201; had this code for couple months, haven't tracked down the cause yet (replaced fuel injector twice, new pigtail, new spark plug etc.) When the code occurs, there is a slight miss on cylinder 1 but otherwise doesn't impact driveability around town.
Clock spring is bad - Turn signal, exterior lights, and headlight issues. Sometimes these work, other times they are on and off randomly depending on steering wheel position. Planning to replace the clock spring but haven't done it yet.

No new engine codes, just the P0201 showing up last night.

I ran across all sorts of posts on different forums related to a faulty clockspring causing driveability issues and their being a common ground? Do you think my bucking and fuel cuts could be clockspring related? Is there a way to quickly disconnect the clock spring on the side of the road just to get home and repair it correctly?
 
Update on my issue. Cleared my codes and began driving home. After driving it another 4 or 5 miles it ran really rough again and my check engine light came on. I pulled off and scanned my codes and got several codes this time; P0201, P0300, P0301, P0304, P0305, P1494, P0138.

Previous to this current issue, my only code that would ever show up was P0201 and only intermittently.

I managed to get home, slowly at times. I'm going to start with a new set of spark plugs and ignition coil.

Anything else I should be looking at?
 
Well, you're basically misfiring on all cylinders. Since you have a coil pack ignition I think that makes the coil unlikely since it would require all 3 coils to fail together. It never hurts to pull a couple of plugs and check their condition, or if you know they're pretty old might as well change them.

201 indicates a mechanical or electrical problem with the injector or its wiring on cyl 1. I don't know if a lack of fuel pressure can do something the pcm could interpret as a mechanical problem but I would be checking the fuel pressure. The fact that it seems to happen only at periods of highest fuel consumption still points me to that as a potential cause.
 
freedom_in_4low said:
Well, you're basically misfiring on all cylinders. Since you have a coil pack ignition I think that makes the coil unlikely since it would require all 3 coils to fail together. It never hurts to pull a couple of plugs and check their condition, or if you know they're pretty old might as well change them.

201 indicates a mechanical or electrical problem with the injector or its wiring on cyl 1. I don't know if a lack of fuel pressure can do something the pcm could interpret as a mechanical problem but I would be checking the fuel pressure. The fact that it seems to happen only at periods of highest fuel consumption still points me to that as a potential cause.
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Still new to the Jeep world, probably a stupid question.... aren't all 6 coils part of one assembly? The pictures I see make it look like one common rail with coils coming off of it.
 
Pacman0939 said:
Still new to the Jeep world, probably a stupid question.... aren't all 6 coils part of one assembly? The pictures I see make it look like one common rail with coils coming off of it.
Click to expand...

it's a common assembly but it's not a single coil inside, it's 3 different coils built into it. So if a coil were to fail, it should result in misfires on a specific pair of cylinders, not all of them, and it's unlikely all three would fail in this manner simultaneously. To kill all 3 at once would be like a broken conductor somewhere in the wiring but that should just make it quit running entirely.

FWIW, I had a coil (on a 99 TJ, which only has one coil) fail in 2020 and it would crank all day and never started at all. I've had fuel pumps fail and do exactly what you're describing.
 
x2. When my fuel pump was failing, there was intermittent sputtering and power loss, but if I let off accelerator to reduce rpms it would resolve...until it would happen again when moving more fuel at higher rpms.
 
I'll go ahead and replace the fuel pump and spark plugs and see where that leaves me. I see most recommend the Bosch 67726 fuel pump but it doesn't look like it's available any longer. What pump would you recommend for my 2004 4.0?
 
Pacman0939 said:
I'll go ahead and replace the fuel pump and spark plugs and see where that leaves me. I see most recommend the Bosch 67726 fuel pump but it doesn't look like it's available any longer. What pump would you recommend for my 2004 4.0?
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that's a lot of work and expense to go through instead of just checking the fuel pressure.
 
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freedom_in_4low said:
that's a lot of work and expense to go through instead of just checking the fuel pressure.
Click to expand...
Looks like you were right on the money but for another reason. Went for a short test drive and yesterday after work, at first it was running smoothly but then the same symptoms started again. Got back home and just happened to notice a very small wet spot under the rear of the Jeep. Smell test confirmed it was gasoline.

Upon further inspection I found a botched fuel line repair from a previous owner. Looks like the fuel line began to leak so they covered it in a piece of vinyl hose and added some clamps.
https://imgur.com/a/nNv0tbz

How easy is this going to be to repair?
 
I don’t think it’s gonna be that complicated but be careful the fuel is under pressure

I was under a Cherokee one time and got gas in my ear

It was one of the scariest and most painful things I’ve ever experienced
 
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Any idea what the part number is for this section of fuel line? Does it have connectors at each end that I can get to? Or am I better off just getting a couple hose barbs, clamps, and a short piece of hose?
 
Pacman0939 said:
Looks like you were right on the money but for another reason. Went for a short test drive and yesterday after work, at first it was running smoothly but then the same symptoms started again. Got back home and just happened to notice a very small wet spot under the rear of the Jeep. Smell test confirmed it was gasoline.

Upon further inspection I found a botched fuel line repair from a previous owner. Looks like the fuel line began to leak so they covered it in a piece of vinyl hose and added some clamps.
https://imgur.com/a/nNv0tbz

How easy is this going to be to repair?
Click to expand...
Before you fix that fuel line, pull the fuel pump relay under the hood. Then try to start the engine. It will spitter but not start. That will relieve the fuel pressure in the line. Disconnect negative battery terminal. Then you can take care of your repair.
 
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AndyG said:
I don’t think it’s gonna be that complicated but be careful the fuel is under pressure

I was under a Cherokee one time and got gas in my ear

It was one of the scariest and most painful things I’ve ever experienced
Click to expand...

wow. Never had it in my ear but I've had it run down into my armpit while changing a fuel filter and that was shockingly burn-y. The skin in your ear canal is the thinnest on the entire body...really anywhere with mucous membrane or thin or particularly sensitive skin isn't going to like gasoline.
 
freedom_in_4low said:
wow. Never had it in my ear but I've had it run down into my armpit while changing a fuel filter and that was shockingly burn-y. The skin in your ear canal is the thinnest on the entire body...really anywhere with mucous membrane or thin or particularly sensitive skin isn't going to like gasoline.
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It went all the way down my eustachian tube instantly

To make it worse my young wife at the time thought that I was on fire and starts spraying me with the blame water hose trying to help- it didn’t.

I’m not trying to sound gruesome but ever since that incident I’ve always been afraid that people that wanted to torture people would use gas in syringes-

It was unimaginable.

All I can remember now was going in and laying on the bed , I was out of my mind in pain
 
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Fixed my leaky fuel hose temporarily by tightening the exisitng clamps a little more with a ratchet. My bucking/cutouts improved slightly.

Finally got my fuel pressure tested. Ended up having a shop test/diagnose as I've been busy with work. Above 2,100 RPM they showed fuel pressure dropping to 26PSI before bouncing back up. 2,100 RPM and below bounced between 39 and 43 PSI.

Which fuel pump assembly do you recommend? I see several options on RockAuto. I understand the Bosch isn't manufactured any longer.
 
Pacman0939 said:
Fixed my leaky fuel hose temporarily by tightening the exisitng clamps a little more with a ratchet. My bucking/cutouts improved slightly.

Finally got my fuel pressure tested. Ended up having a shop test/diagnose as I've been busy with work. Above 2,100 RPM they showed fuel pressure dropping to 26PSI before bouncing back up. 2,100 RPM and below bounced between 39 and 43 PSI.

Which fuel pump assembly do you recommend? I see several options on RockAuto. I understand the Bosch isn't manufactured any longer.
Click to expand...
I believe you can still get the Bosch pumps, but not with the complete built housing assembly. I've used Delphi in many vehicles with good results.
 
AndyG said:
I don’t think it’s gonna be that complicated but be careful the fuel is under pressure

I was under a Cherokee one time and got gas in my ear

It was one of the scariest and most painful things I’ve ever experienced
Click to expand...
I was replacing a fuel pump on a Chrysler van once and forgot to relieve the fuel pressure before disconnecting the line. The connector above the tank is on a small jog in the line, so the disconnected line to the engine points directly downwards. I was right underneath it when I disconnected it and got the full column of high-pressure fuel blasted into my face. It went into my eyes, up my nose, and into my mouth. Of course I flinched and bashed my head on the bottom of the van. I managed to crawl out of under the van but I couldn't breathe, I couldn't see, and I was disoriented due to bashing my head. It took what felt like an eternity to be able to get a breath in, and about a minute before I could see again. There was an intense burning sensation in my nose and throat for a few hours afterwards, and I couldn't breathe or see normally until the next morning.

Don't be dumb like me, relieve fuel pressure before you do ANYTHING with a fuel line.
 
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