Sputtering and losing power

Tjwithatj

Tjwithatj

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Feb 19, 2018
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Alabama 36, Hartselle, AL, USA
Hey guys, ive recently had a check engine light come up on my 97 4.0. When I get on the gas my jeeps wants to sputter and seem like its losing power. I can drive it normal just in low rpms. I pulled the codes P0123, P0441 and P0121.

Ive done some research and so I took out the throttle body and cleaned it .... still sputtering.I also read that the clockspring could've possibly gone bad. Ever since ive had the jeep its had an airbag light, word on the street is that theres a harness under the steering wheel you can unplug and it fix the problem. I guess what I'm getting at... do these three codes mean anything specific? Has anyone else had this problem?

ALSO, I have a cold air intake and I was offroading a little bit in some mud... then when I get on the highway is when the light came on and I started having issues. Maybe need to change out my filter ?? Anything helps thanks folks
 
Does it drive normally when the engine is cold but gets rough as the engine warms up? I'm primarily thinking it could be a bad throttle position sensor though.

I'd also consider going back to the OE air intake system. Within reason the OE air intake is better at keeping water & mud out. Not to mention the air filters I've seen on CAI's are not good air filters (K&N's are especially notoriously bad at filtering the air), plus that CAI is not really (!) helping performance.
 
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Jerry Bransford said:
Does it drive normally when the engine is cold but gets rough as the engine warms up? I'm primarily thinking it could be a bad throttle position sensor though.

I'd also consider going back to the OE air intake system. Within reason the OE air intake is better at keeping water & mud out. Not to mention the air filters I've seen on CAI's are not good air filters (K&N's are especially notoriously bad at filtering the air), plus that CAI is not really (!) helping performance.
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It still continues to do it when its cold. The jeep was already equipped with a CAI and a snorkel when I bought it. The snorkel is not hooked up though. Also ive heard a lot of people replacing the TPS but that not being the issue, so I really wanted to see what I could do at no cost first.
 
Jerry is right about the cold air intakes not being good air filters. They're absolutely horrible on TJs, especially with as much crap as they let through.

Have you tried replacing the TPS (throttle position sensor) with an OE Mopar unit? If you replace it, it MUST be an OE Mopar sensor.

Another thing would be to check for vacuum leaks, only because one of those codes is indicative of them.

In the long run, I'd look to replace the CAI with a stock airbox if possible. Especially if you do any off-roading!
 
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Tjwithatj said:
Also ive heard a lot of people replacing the TPS but that not being the issue.
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Some people throw parts at problems without knowing what they're doing or using any of the diagnostic tools to help guide them. Two of your diagnostic codes are indicating the computer thinks there's a problem with the TPS. I have had a bad TPS on my previous TJ and my wife's previous Grand Cherokee and both created symptoms similar to what you have described. No guarantees but at least the TPS is not that expensive. And as Chris recommended above, I'd skip cheap aftermarket TPS's sold by low-end stores like Autozone and go for the Mopar. I won't go cheap on sensors, they're too critical to the engine's proper running.
 
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Just so you know also, you can test the TPS sensor using the procedure outlined in the FSM. Then you can be sure as to whether or not it's your TPS sensor. That would at least rule it out before wasting your money on one!
 
Jerry Bransford said:
I'd skip cheap aftermarket TPS's sold by low-end stores like Autozone and go for the Mopar. I won't go cheap on sensors, they're too critical to the engine's proper running.
Click to expand...

Ahhh Jerry, what are we going to do once Mopar ceases production of all the sensors for the 4.0? Just live with check engine lights I guess, huh?
 
Chris said:
Jerry is right about the cold air intakes not being good air filters. They're absolutely horrible on TJs, especially with as much crap as they let through.

Have you tried replacing the TPS (throttle position sensor) with an OE Mopar unit? If you replace it, it MUST be an OE Mopar sensor.

Another thing would be to check for vacuum leaks, only because one of those codes is indicative of them.

In the long run, I'd look to replace the CAI with a stock airbox if possible. Especially if you do any off-roading!
Click to expand...
In addition to a few other symptoms (bucking and stalling, probably some others), yesterday it began sputtering (even cold) and I have to put the pedal close to the floor to get the RPMs over 2000. No codes. And I noticed a gas smell from the exhaust today. Am I looking at the TPS too?

PS I have a CAI as well.
 
Jerry Bransford said:
Does it drive normally when the engine is cold but gets rough as the engine warms up? I'm primarily thinking it could be a bad throttle position sensor though.

I'd also consider going back to the OE air intake system. Within reason the OE air intake is better at keeping water & mud out. Not to mention the air filters I've seen on CAI's are not good air filters (K&N's are especially notoriously bad at filtering the air), plus that CAI is not really (!) helping performance.
Click to expand...
In addition to a few other symptoms (bucking and stalling, probably some others), yesterday it began sputtering (even cold) and I have to put the pedal close to the floor to get the RPMs over 2000. No codes. And I noticed a gas smell from the exhaust today. Am I looking at the TPS too?

PS I have a CAI as well.
 
Chris said:
Jerry is right about the cold air intakes not being good air filters. They're absolutely horrible on TJs, especially with as much crap as they let through.

Have you tried replacing the TPS (throttle position sensor) with an OE Mopar unit? If you replace it, it MUST be an OE Mopar sensor.

Another thing would be to check for vacuum leaks, only because one of those codes is indicative of them.

In the long run, I'd look to replace the CAI with a stock airbox if possible. Especially if you do any off-roading!
Click to expand...
...and I replaced the fuel pump 2 weeks ago too
 
Jerry Bransford said:
Does it drive normally when the engine is cold but gets rough as the engine warms up? I'm primarily thinking it could be a bad throttle position sensor though.

I'd also consider going back to the OE air intake system. Within reason the OE air intake is better at keeping water & mud out. Not to mention the air filters I've seen on CAI's are not good air filters (K&N's are especially notoriously bad at filtering the air), plus that CAI is not really (!) helping performance.
Click to expand...
...and I replaced the fuel pump 2 weeks ago too
 
Jerry Bransford said:
Some people throw parts at problems without knowing what they're doing or using any of the diagnostic tools to help guide them. Two of your diagnostic codes are indicating the computer thinks there's a problem with the TPS. I have had a bad TPS on my previous TJ and my wife's previous Grand Cherokee and both created symptoms similar to what you have described. No guarantees but at least the TPS is not that expensive. And as Chris recommended above, I'd skip cheap aftermarket TPS's sold by low-end stores like Autozone and go for the Mopar. I won't go cheap on sensors, they're too critical to the engine's proper running.
Click to expand...
I have a 02 TJ has 187000mi on I got a misfire code on cyl1-5 then moved to 1-3 this all happens after warm up. I have installed new 4 hole injectors, new plugs, new coil pack. Drove it about 300 miles now runs bad again any ideas.
 
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