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Discussion Starter · #1 ·
Hello guys,

Just purchased a new TJ 97 2.5 4cyl 5 spd. First TJ, previously owned an XJ.
The jeep has 182k and is in great condition no rust, maintenance records, etc.

Im having an issue where the jeep will seem to not respond to the gas pedal when accelerating. I have not experienced this issue once out of 2nd gear. Eventually (5-10 seconds) it will return to normal functionality. This also does not happen all of the time (random).

When idling, it remains fairly steady but it does move RPM's but not drastically at all.

Wanted to get your opinions on it before i start throwing parts at it. Thanks
 

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Discussion Starter · #2 ·
Was trying to keep it short, but realized it probably did not give enough information.

It does not stall when this is happening. It seems to sputter or buck back and forth and the rpms will remain over 1k but will move rapidly up and down.
 

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I think I would start by removing the throttle body and and give it a thorough cleaning, it can be done in place but for the sake of a $3 gasket it a lot easier on the bench and you know the seal to the manifold is good when it's re-installed. I would also borrow/rent a fuel pressure gage and get a pressure reading on the fuel pump. On the 97' there should be a test port on the fuel rail and you should read a steady +/- 49 psi at idle.

If you google throttle body there are quite a few re-build threads.
 

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Discussion Starter · #5 ·
Cleaned throttle body and replaced the TPS (mopar).

Still having idling issues, so will drive it a few hundred miles until i just replace IAC.

I am still having this sputtering issue. It only happens after vehicle has been turned off and in second gear. I will shift to second and it will start to accelerate and right around 2k+ rpms it will just go crazy and the rpms will move up and down with no trottle response. This happens for about 15 seconds and if i let off gas and hit pedal it will eventually stop.

Not sure what parts to replace?
 

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A couple times I had a milder version of this. No idle problems or rpm variations but it went flat in second gear a couple times. I changed the plugs (looked old) and didn't have it for a long time. It went flat in second again the other day.

I'll probably do the cap, rotor and wires 'cause they look old too.

Curious about the second gear thing, huh?

I'll post back here if I get any ideas.
 

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I also have a 97 TJ 2.5L. I had this same exact problem. It was the ALTERNATOR! It was dying. I had no idea a bad alternator could cause this issue. I went through replacing a bunch of unnecessary things until my alternator finally completely died. Then replaced it. never sputtered again.

Have someone check your alternator. Keep us updated on what happens.

Good luck.
 

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Can the auto parts store check this alternator like they check all of the others?

I got my alternator from the junkyard when I got my Jeep going. Bad alternator wouldn't surprise me.
 

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Power has to be steady and stable for these car computers to work. Alternators are really important in modern vehicles. However, the alternator is a fairly easy test. Any auto parts store should be able to test it for you.

TJ4Jim's counsel is the best starting point. A clean throttle body is a good first step.
 

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Discussion Starter · #10 ·
Alternator is relatively new. Was replaced in 2012, but has less than 10k on it. Vehicle sat from 2013 until now (garaged). Not saying it isn't bad but the thing looks like it just came out of the box. Which actually might explain it.

Ill have to look into it but it never crossed my mind. Could it be the battery? I have heard of those causing weird issues. No idea how old that thing is or where it came from.
 

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Garaged for four years? Holy cow!

If you haven't changed all the fluids and fuel was left in the tank for four years, you've got fuel delivery problems. The fuel system has to be in poor shape, I'd think.

Check your fuel pressure, at the rail, which can't be done easily on a '97 as there is no Schrader valve on the rail - have to use an adapter connected between the rail and supply line. But, I'm thinking you'll need a new fuel pressure regulator and possibly a fuel pump. Might as well just replace the whole fuel pump if you wind up having to drop the tank for a fuel pressure regulator. Clean the tank inside if you put a fuel pump in it.

I assume you have no codes from the computer?
 

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If you have a new alternator then... I don't know. Having it tested shouldn't hurt and probably is very cheap or free. Even then, it rules out one possibility.

You might have to take the advice from everyone else to help diagnose it.

It's weird because I had the same exact issues you described. the same year, the same engine. But similar symptoms don't always lead to the same cause.
 

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Hello guys,

Just purchased a new TJ 97 2.5 4cyl 5 spd. First TJ, previously owned an XJ.
The jeep has 182k and is in great condition no rust, maintenance records, etc.

Im having an issue where the jeep will seem to not respond to the gas pedal when accelerating. I have not experienced this issue once out of 2nd gear. Eventually (5-10 seconds) it will return to normal functionality. This also does not happen all of the time (random).

When idling, it remains fairly steady but it does move RPM's but not drastically at all.

Wanted to get your opinions on it before i start throwing parts at it. Thanks
Mine is doing this as well except mine occurs soon after cranking it and always in first gear. I also have a 2.5L 97 Jeep Tj
 

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Mine is doing this as well except mine occurs soon after cranking it and always in first gear. I also have a 2.5L 97 Jeep Tj
Mine is first time accelerating after starting the Jeep, warm or cold. Yesterday it did it in first gear. Parking lot on a slope and when I turned to go uphill it didn't take the gas for a moment.

It has only done it a few times but I'm afraid it might get worse.
 

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Discussion Starter · #16 ·
When i picked it up it actually had no fuel in the tank, but then again the gas gauge doesn't work ( and hasn't for a while according to the documentation). Im going to get the fuel pressure looked at.

Im going to have to bring it to someone to have looked at. I went to advance auto and they gave me a hard time about reading the alternator and they don't let you run the test.

Its actually quite dangerous. I was also in a parking lot today with it, and started up fine drove out of the lot. Stopped. Then accelerated to the main road and right in the middle of the road no response until i hammered on the throttle.

Not sure if related but because i am having idling issues, check engine light just came on. Gonna pull the codes and post them up. I cleaned the throttle body, replaced TPS and now the idle is worse then before. Put new gasket in and rtv'd the iac housing. Replacing the IAC as soon as the part gets in as well.
 

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Discussion Starter · #17 ·
Whats strange about the idle is that once I start the vehicle it will go to the first gauge on the dash and sound like it is going to die. Once i start to drive and then stop it will be fine but idle around 1k give or take 100rpm that it fluctuates.
 

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Yep. Sounds so familiar.

Nobody knew what I was talking about. People thought it was in my head or making it up. I even went as far as letting a friend borrow my jeep for the day to prove what it was doing, and he experienced it too. Then, I started recording it.

Like I said, eventually it just completely died on me, and then got my alternator replaced and never had that problem again.

For you, it could be something else, so I'm curious what it will be when you find out.
 
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