Jerking / Bucking Before Shift

jordans05tj

jordans05tj

TJ Enthusiast
Supporting Member
Joined
Dec 31, 2019
Messages
232
Location
Arkansas
So I've got a 2005 TJ with the straight 6 and a 6-speed, 120k miles. As I come to the top of a gear to where I need to shift, it starts violently jerking and bucking but immediately stops when I depress the clutch and shift, only to continue at the top of the next gear. It doesn't do it all the time and it seems like it's not as bad when it's warmer outside. The tach doesn't show any RPM change while it's bucking. I'm already having a shop do the exhaust manifold gasket on it, the smoke test showed a bad leak. While I had them diagnosing that, they found an Oxygen sensor code (probably related to the leak, and I replaced the sensor it said already), and I've got a camshaft position sensor intermittent code. I already upgraded the oil pump drive and replaced the sensor with a Mopar replacement. It takes forever to start on cold mornings, but once the temperature outside warms up it start perfectly. I recently put a clutch in it and I thought it might be a transmission problem, but my transmission guy says it sounds like a motor problem. It's got <6 months old spark plugs, Mopar cam position sensor, fuel pump, and I'm sure I'm leaving stuff out. I've had this Jeep since March and I'm not sure what to look for being as new to it as I am. Any help would be appreciated, thanks in advance
 
It's jerking because you're going into limp mode. Can you post the specific code(s)? I assume P0344, but are there others?

jordans05tj said:
... and I've got a camshaft position sensor intermittent code. I already upgraded the oil pump drive and replaced the sensor with a Mopar replacement.
Click to expand...

This is almost certainly the problem. The only sensor that works over time is the one that was installed at the factory. Even the current Mopar sensor causes problems.

I'm not really sure what to recommend other than replacing the CMP sensor again or trying to find an OE sensor. I've replaced my OPDA a few times and the Dorman and Crown sensors both set P0344. I went back to the OE sensor a couple years ago and haven't had any further issues.

I know that Dorman, Crown and Mopar sensors won't work. Maybe NTK, Standard or Holstein? It would probably be a good idea to also keep a spare of any brand around since they all seem to work for a while.

When you replace the sensor you may also want to disconnect the battery to reset the PCM. This will allow it to pick up the signal from the new CMP right away.
 
  • Like
Reactions: Chris
I don't remember the number but I may be able to get it down to O'Reilly and run them. The other day at the shop I looked at the connector and it wasn't completely plugged in and the little red clip wasn't locked so I plugged it all back up and he cleared the code. Ran fine going back home about a mile up the road. The light is back which could be just the O2 sensor, but it still jerked and took forever this morning. I've still got the factory sensor in a box, but I had a code for it before I did the OPDA. Should I try putting the original sensor back in? I've also got the crown sensor that came with my OPDA but I've heard they aren't worth putting in anyway.
 
With your 05 TJ you do not need a scanner to read codes. Turn the ignition from OFF to ON 3 times without starting the engine. Any stored codes will be displayed in the odometer.
 
  • Like
Reactions: Chris
You just blew my mind lol I had no idea it would do that, thanks for the tip. The codes are P0141 and P0340
 
P0340 - Camshaft Position Sensor Circuit Malfunction.

Most likely an issue with the sensor. Could also be a short in the wiring between the sensor and the PCM. If you have the Crown sensor available to swap, I would use it and see if the issue goes away, at least for the time being. If you're currently experiencing a crank/no start condition, it may be helpful to disconnect the battery to reset the PCM to factory parameters after replacing the sensor. If you don't do this, the PCM's adaptive memory may use the inputs it previously received from the faulty sensor.

P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

Bank 1 is the front of the engine (think cylinder 1), sensor 2 is the one mounted after the mini cat. The heater circuit is not working. Could be that the sensor is bad, the connector is corroded/contaminated, or there is a wiring issue between the PCM and the sensor. Simplest thing to do is inspect the wiring harness. If you have a multi-meter, you can Google how to test the sensor wiring.

Perhaps others will chime. If you follow up, we can troubleshoot further.
 
  • Like
Reactions: Blondie70
I'll get that crown sensor put in first thing tomorrow and see what it does, I typically undo the battery any time I do any sensors or anything. I can try to trace some wiring on both it and the O2 sensor also. Could the exhaust leak around the manifold also throw the O2 sensor code? It's getting fixed either way because of that obnoxious ticking, I was hoping it would solve that code too since I replaced the sensor already.
 
  • Like
Reactions: Offline246
jordans05tj said:
Could the exhaust leak around the manifold also throw the O2 sensor code? It's getting fixed either way because of that obnoxious ticking, I was hoping it would solve that code too since I replaced the sensor already.
Click to expand...

An exhaust leak will not cause P0141. If you've already replaced the sensor then you'll need to check the wiring harness.

It is fairly common that the flange bolts from the down pipe to the exhaust manifold back out and create a leak. You'll get a ticking sound followed by a code if it gets real bad. When you check the bolts, beware that they can back out and rust in place so even though the seem tight, they may not be holding the flange against the manifold.
 
I put that crown sensor back in it, it started right up and never did anything else I've described. I guess I'll warranty out that Mopar sensor and keep it as a spare. Nothing in the wiring for the cam sensor looked wrong so it seems like you were right about the sensor, thanks for the help with that.

I'll have to go trace wiring for the O2 sensor, if I find anything I'll keep this updated. I'm having a shop do the gaskets because I don't have the time to do it and A/C lines need to come off, but they told me the same thing about those bolts and I trust them to get it right.
 
I can't find anything unusual with the O2 sensor wiring, the plug was hanging down off of it's little hanger but it wasn't contacting anything. I've heard people recommend the NGK O2 sensors for it, should that be my next step?
 
jordans05tj said:
I can't find anything unusual with the O2 sensor wiring, the plug was hanging down off of it's little hanger but it wasn't contacting anything. I've heard people recommend the NGK O2 sensors for it, should that be my next step?
Click to expand...
Replace all 4 if you can. RockAuto usually has a good price on the NTK/NGK sensors.

I recommend having an oxygen sensor socket and maybe a 7/8" crow foot (go for the 6 or 12 point if you can) wrench on hand. Makes the job super easy.
 
I was under the impression that you had already replaced the 1/2 Oxygen Sensor. If yes, and you used anything other than NTK/NGK, that could be why the code remains. Without diagnosis though, you may be unnecessarily replacing parts.

Testing 02 Sensor Heater Circuit:
 
If that jerking is right around 2500 rpm that's the CPS code as AjRagno said. If you sit at idle and rev it, it should only go to about 2500 and hit a soft rev limiter, if that's the case. It's just really violent feeling when you're driving. I had this happen recently after a slow crank situation with a bad starter ground. It just confused the computer and a PCM reset fixed it. That's the absolute first easy thing to try.
 
05 6 speed CPS code that was fixed with a PCM reset. Not saying that yours will be fixed, but just sharing the condition.
 

Attachments

  • VID_20191219_110002.mp4
    20 MB
bluescapegoat said:
05 6 speed CPS code that was fixed with a PCM reset. Not saying that yours will be fixed, but just sharing the condition.
Click to expand...
I have noticed that rev limiter sitting still, but I replaced the cam sensor with the crown unit my OPDA came with and it starts right up and drives perfectly. No more P0340 either. I've got my local dealer getting me a replacement Mopar unit, I'll keep it as a spare until this crown one quits working. If I continue having problems what all is involved in resetting the PCM like you mentioned?
 
AjRagno said:
I was under the impression that you had already replaced the 1/2 Oxygen Sensor. If yes, and you used anything other than NTK/NGK, that could be why the code remains. Without diagnosis though, you may be unnecessarily replacing parts.

Testing 02 Sensor Heater Circuit:
Click to expand...
You're correct, I originally replaced it with a Mopar sensor and the code remained. I put in an NTK sensor Wednesday, drove it probably 30 miles and lo and behold, P0141 came back 😒

I'll watch that video and see what he has to say, but I'm beginning to wonder if I just can't find any wiring problems that may exist. Is there any other possible cause of that code? Cats, exhaust leaks, etc? Monday morning I'm having a shop do that exhaust manifold gasket, I'm probably going to let them look at solving this issue also if I can't find the problem before then.
 
Steel City 06 said:
Replace all 4 if you can. RockAuto usually has a good price on the NTK/NGK sensors.

I recommend having an oxygen sensor socket and maybe a 7/8" crow foot (go for the 6 or 12 point if you can) wrench on hand. Makes the job super easy.
Click to expand...
I'm too stubborn to buy those sockets, but if I have to keep doing this with a crescent wrench I may change my mind 🤣

I'll check their prices at Rock Auto if the problems remain, but I have an account I can use down at O'Reilly with a pretty generous discount
 
jordans05tj said:
I have noticed that rev limiter sitting still, but I replaced the cam sensor with the crown unit my OPDA came with and it starts right up and drives perfectly. No more P0340 either. I've got my local dealer getting me a replacement Mopar unit, I'll keep it as a spare until this crown one quits working. If I continue having problems what all is involved in resetting the PCM like you mentioned?
Click to expand...

Just like clearing the codes by unhooking the battery. Instead of waiting over night or something like that, I just disconnect the leads from the battery and touch them together to drain the system. I've been playing with the PCM in my Jeep a lot lately and that's quick and easy. Don't bridge the contacts on the battery itself.
 
jordans05tj said:
You're correct, I originally replaced it with a Mopar sensor and the code remained. I put in an NTK sensor Wednesday, drove it probably 30 miles and lo and behold, P0141 came back 😒

I'll watch that video and see what he has to say, but I'm beginning to wonder if I just can't find any wiring problems that may exist. Is there any other possible cause of that code? Cats, exhaust leaks, etc? Monday morning I'm having a shop do that exhaust manifold gasket, I'm probably going to let them look at solving this issue also if I can't find the problem before then.
Click to expand...

Sorry I didn't include Mopar (OE) as sensors that will work. There are lots of reports of Bosch in particular not working in our TJs and that is what seems to be most readily available at parts stores.

P0401 is for the 02 sensor Heater Circuit. Clogged/Bad cats or exhaust leaks will not set this code. If it is not the sensor itself then it's either the wiring or the PCM. It's been my experience that if it's the PCM you would have codes for all of the 02 sensors so it's more likely an issue with the wiring harness between the 02 sensor connector and the PCM or between the 02 sensor connector and the sensor ground.

To test the wiring you'll need a multi-meter. You can also reference the service manual here: https://wranglertjforum.com/threads/jeep-wrangler-tj-factory-service-manuals-fsm-technical-documentation.4618/

Heater Circuit K299 18BR/WT
Ground Circuit Z43 18BK/LB

The service manual shows that the 1/2 and 2/2 sensors share a ground point of G105, which is that stud on the passenger side of the engine block, near the dipstick tube. The wires spice at S185, which looks to be that plastic loom housing behind the valve cover. Since the 2/2 sensor is working, if it's a ground issue with sensor 1/2, the issue is between this spice and the sensor connector.

If the ground circuit is good, disconnect and remove the battery and test for resistance between the sensor connector and the PCM's C3 connector, terminal 9.

When testing the wiring, it would also be helpful to have another person who can manipulate the harness to see if doing so changes the resistance.
 
Top Bottom
Back