99 TJ 2.5 L Engine RPMs drop to 2grand or stalls at stop - JeepForum.com

 
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post #1 of 11 Old 02-20-2016, 02:00 PM Thread Starter
eagleboys27
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99 TJ 2.5 L Engine RPMs drop to 200 or stalls at stop

This has been a problem for the past month or so... Whenever the jeep is cold and when I come to a complete stop 1 of three things will happen.

1. Good solid idle.
2. Idle drops to 2-3hundred kind of *kicks* then goes back to normal
3. Idle drops and stalls the car

When 2 or 3 happen the whole car starts to shake as well. The RPMs also drop when I am braking sometimes. This is super annoying and I don't know what is going on. Been in two diffrent shops for over 10 hours trying to diagnose the problem but with no engine light they can't figure anything out...


-99 Tj Jeep Wrangler 2.5 Liter

Last edited by eagleboys27; 02-20-2016 at 03:43 PM.
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post #2 of 11 Old 02-20-2016, 03:26 PM
TJ4Jim
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Quote:
Originally Posted by eagleboys27 View Post
This has been a problem for the past month or so... Whenever the jeep is cold and when I come to a complete stop 1 of three things will happen.

1. Good solid idle.
2. Idle drops to 2-3 grand kind of *kicks* then goes back to normal
3. Idle drops and stalls the car

When 2 or 3 happen the whole car starts to shake as well. The RMPS also drop when I am braking sometimes. This is super annoying and I don't know what is going on. Been in two diffrent shops for over 10 hours trying to diagnose the problem but with no engine light they can't figure anything out...
I assume you mean it drops to 2-3 hundred RPM not grand.

If so I would start by cleaning the idle air control on the throttle body, good place to begin.
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post #3 of 11 Old 02-20-2016, 03:31 PM Thread Starter
eagleboys27
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Originally Posted by TJ4Jim View Post
I assume you mean it drops to 2-3 hundred RPM not grand.

If so I would start by cleaning the idle air control on the throttle body, good place to begin.
Ive done this! And yeah 2-300 sorry, edited it. Also got a new IAC after 5 hours at Pep Boys and they came out with it all disassembled. Feel like they just broke it to find some type of problem and get me out because the way it looked it seems like jeep would've ran way worse, replaced it and no solution.

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post #4 of 11 Old 02-20-2016, 03:35 PM
TJ4Jim
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You can replace the IAC but the seat which is a separate part can still be dicked up. You may just want to remove the entire TB and give it a good going over.

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post #5 of 11 Old 02-20-2016, 03:38 PM Thread Starter
eagleboys27
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Originally Posted by TJ4Jim View Post
You can replace the IAC but the seat which is a separate part can still be dicked up. You may just want to remove the entire TB and give it a good going over.

I cleaned it about a week ago with TB cleaner and some q-tips. Didn't seem to help too much. Its annoying cause I just can't seem to figure out the problem let alone fixing it.

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post #6 of 11 Old 02-20-2016, 03:44 PM
TJ4Jim
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Originally Posted by eagleboys27 View Post
I cleaned it about a week ago with TB cleaner and some q-tips. Didn't seem to help too much. Its annoying cause I just can't seem to figure out the problem let alone fixing it.
What brand IAC was it replaced with. Aftermarket is notorious for causing problems. Are you getting a check engine light at all.

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post #7 of 11 Old 02-20-2016, 04:02 PM Thread Starter
eagleboys27
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Originally Posted by TJ4Jim View Post
What brand IAC was it replaced with. Aftermarket is notorious for causing problems. Are you getting a check engine light at all.
"BWD Idle Air Control Valve" looked it up, must be made by CARQUEST. And no, no engine light

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post #8 of 11 Old 02-20-2016, 04:33 PM
TJ4Jim
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Not sure what to tell you. The symptoms point to an IAC issue so if you sure the TB is clean many will tell you to get the OEM part and replace it.

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post #9 of 11 Old 02-21-2016, 08:45 AM Thread Starter
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*bump*... still no fix

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post #10 of 11 Old 02-22-2016, 03:24 PM Thread Starter
eagleboys27
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Just tried pulling the horn relay. Someone said it might be the clock spring the TPS is connected through may be faulty... long shot but hopeful for any other fixes

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post #11 of 11 Old 04-03-2016, 09:48 AM Thread Starter
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Happening still! Very annoying. The RPMS will either bounce from idle to 200 a few times at a stop or one large drop at a stop. Also does it in somewheere like a drive through if i just tap on the gas... goes from 1,200 then drops real low to 200 or stalls.

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2.5 liter , idle issue , rough idle , rpms

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