Sluggish acceleration and bad smell while driving uphill

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Erica 111112

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May 28, 2022
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Florida
I have a 2012 JK with 64k miles. It’s mainly used to drive around town. I live in Florida so mostly flat ground. Today I was at the beach and had a rather steep bridge to cross. The acceleration felt sluggish and as I pressed harder on the gas it kind of bucked/jerked as it accelerated, smelt a burning smell and my check engine light came on momentarily. This happened a second time on this trip and as soon as I shut the ac off it drove completely fine.

I’ve also noticed that when running the ac and stopped at a light the truck will occasionally surge/buck.

What could this be? Mass Air Flow, vacuum issue? Power issue. Only seems to happen when ac running. The acceleration and burning smell has me really worried. Thanks!
 
Erica 111112 said:
I have a 2012 JK with 64k miles. It’s mainly used to drive around town. I live in Florida so mostly flat ground. Today I was at the beach and had a rather steep bridge to cross. The acceleration felt sluggish and as I pressed harder on the gas it kind of bucked/jerked as it accelerated, smelt a burning smell and my check engine light came on momentarily. This happened a second time on this trip and as soon as I shut the ac off it drove completely fine.

I’ve also noticed that when running the ac and stopped at a light the truck will occasionally surge/buck.

What could this be? Mass Air Flow, vacuum issue? Power issue. Only seems to happen when ac running. The acceleration and burning smell has me really worried. Thanks!
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I would say maybe a problem with the AC Compressor.

You would be getting a CEL if it was anything electronic.
 
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So today it did the same thing ( yet not as severe) without the ac running. If this is not an issue where the ac is involved what would cause the hesitation and bucking when accelerating? I gassed it on flat pavement and it accelerated fine (no bucking) but as soon as I let off the gas it started bucking and then went back to normal. I took it in to an auto parts store to see if the check engine light stored a code when it popped on and unfortunately it didn’t. This seems to be intermittent and just stared happening.
 
Erica 111112 said:
So today it did the same thing ( yet not as severe) without the ac running. If this is not an issue where the ac is involved what would cause the hesitation and bucking when accelerating? I gassed it on flat pavement and it accelerated fine (no bucking) but as soon as I let off the gas it started bucking and then went back to normal. I took it in to an auto parts store to see if the check engine light stored a code when it popped on and unfortunately it didn’t. This seems to be intermittent and just stared happening.
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If it's not setting a CEL code it could be fuel related.
 
BLACKJKU said:
Did it happen soon after putting some gas in it?
Maybe fuel filter problem.
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I normally only fill up to half a tank cause I don’t drive a whole lot but filled a whole tank cause I’m in vacation and it just seems like this started afterwards. I mean I don’t drive around where I have to crazy accelerate a lot either so who knows.
 
Erica 111112 said:
I normally only fill up to half a tank cause I don’t drive a whole lot but filled a whole tank cause I’m in vacation and it just seems like this started afterwards. I mean I don’t drive around where I have to crazy accelerate a lot either so who knows.
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The smell thing is puzzling also, what does it smell like? Fuel fumes, oil, rubber?
 
BLACKJKU said:
The smell thing is puzzling also, what does it smell like? Fuel fumes, oil, rubber?
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Definitely not rubber. I don’t know if I could distinguish between burning fuel and oil. It almost reminds me of the smell of an overheating engine. The smell goes away and quickly as it appears too. Temp gauge doesn’t go up on dash either. I did check under the hood & I’m not seeing anything leaking. I went ahead and checked air filter and it’s super clean. The ac is also running super cold. No loud noises from ac. So I’m guessing it’s not the ac compressor.
 
Erica 111112 said:
Definitely not rubber. I don’t know if I could distinguish between burning fuel and oil. It almost reminds me of the smell of an overheating engine. The smell goes away and quickly as it appears too. Temp gauge doesn’t go up on dash either. I did check under the hood & I’m not seeing anything leaking. I went ahead and checked air filter and it’s super clean. The ac is also running super cold. No loud noises from ac. So I’m guessing it’s not the ac compressor.
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Catalytic converter comes to mind. Do you know what they look like and where they are located?
 
BLACKJKU said:
If one was bad it would be really hot and if you was to get close to it you could smell it. If you have or could get a IR temp gun it would make it easy to check both of them.
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I drove around a lot today and have been home about an hour. Just touched - its warm but not hot. Would I want to check the temp right after or when it’s been running?
 
Also another issue is the underhood insulation can get sucked over the air intake, but your issue doesn't really sound like that. But might be worth looking at.

Yes right after it's shut off or better yet after it does it if it would be possible. Also don't touch the Cats they can start a pile of leaves on fire it parked over them.

Another thing maybe get some Heet in the yellow bottle and put in your fuel tank, it can help get water out.
 
Erica 111112 said:
I drove around a lot today and have been home about an hour. Just touched - its warm but not hot. Would I want to check the temp right after or when it’s been running?
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After reading on the catalytic converter I’m pretty sure I don’t want to be touching this with my hand at all. Lol. Looks like I should probably go
BLACKJKU said:
Also another issue is the underhood insulation can get sucked over the air intake, but your issue doesn't really sound like that. But might be worth looking at.

Yes right after it's shut off or better yet after it does it if it would be possible. Also don't touch the Cats they can start a pile of leaves on fire it parked over them.

Another thing maybe get some Heet in the yellow bottle and put in your fuel tank, it can help get water out
Click to expand...
 
Yeah I saw the previous posts about the under hood insulation. I don’t have any of that under my hood. My buddy also recommended getting some Heet. I did read a quick article on the cats and you’re right- I don’t want to be touching that with my hand. Lol. I plan on taking the Jeep in for an oil change next week so maybe the mechanic will have some ideas. My uncle (whose owned and worked on jeeps his entire life) said it could be so many things but hard to say without a code reading. Appreciate all your help today!
 
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I don't think "bad" fuel would be an issue these days unless the Jeep sat dormant for a year. Only place I'd believe there's an exception of possibly contaminated fuel would be Miami. 😆 Sound like a bad cat like as @BLACKJKU suggested.

Keep us posted if you have any resolve or find anything you can share.

Best of wishes ✌️
 
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