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2004 PT Cruiser Turbo rough idle #2990003
11/28/21 09:50 PM
11/28/21 09:50 PM
Joined: Jan 2003
Posts: 941
Klamath Falls, Oregon
Dartslantsix Offline OP
super stock
Dartslantsix  Offline OP
super stock

Joined: Jan 2003
Posts: 941
Klamath Falls, Oregon
Just picked up a new car and I need some help diagnosing a rough idle.
Here are the symptoms: cold start is smooth, but as soon as it comes off high idle, it starts to run rough. Anything off idle is smooth, drives fine otherwise.
What I've checked so far: cleaned PCV valve, checked for vacuum leaks on the intake manifold, cleaned throttle body and IAC.
No codes. Unsure of when the car's last tune up was.
I was going to pull the plugs and check them next. Any other things I should be checking?

Car has 174K miles with a newer engine with approximately 50K on it.

Thanks.

-Dave

Last edited by Dartslantsix; 11/29/21 12:31 AM. Reason: add detail
Re: 2004 PT Cruiser Turbo rough idle [Re: Dartslantsix] #2990019
11/28/21 10:51 PM
11/28/21 10:51 PM
Joined: Mar 2007
Posts: 691
Southeast Pa.
SALEM1912 Offline
mopar
SALEM1912  Offline
mopar

Joined: Mar 2007
Posts: 691
Southeast Pa.
Is it really a rough idle or could it be grounded out motor mounts?

Re: 2004 PT Cruiser Turbo rough idle [Re: SALEM1912] #2990065
11/29/21 06:51 AM
11/29/21 06:51 AM
Joined: Sep 2014
Posts: 1,105
Central Pa
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moparjim79 Offline
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moparjim79  Offline
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Joined: Sep 2014
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Central Pa
Originally Posted by SALEM1912
Is it really a rough idle or could it be grounded out motor mounts?


I like where your head is at with this. Usually when the motor mounts shart the bed, its very apparent. O
P.- want to test this theory? Just firmly grab the valve cover and give the engine a few good rocks. Worn mounts will allow the engine to move a few inches fore and aft with no problems. If you find it worn, spend the time and money and replace all of the mounts(3), its worth it. The turbo cars go through them easily. Advance auto used to sell an upper mount that was filled with polyurethane to all but eliminate breakage and not transfer vibration into the cab of the vehicle.

Pull plugs, check condition and the gap- if its a factory replacement engine, make sure your plugs are gapped properly.
While the vehicle is idling, spray a mist of water over the plug wires. Look for sparking. The oem coils on these are good units, the plug wire are known to degrade due to excessive heat from the turbski.
Make sure the throttle body is spotless and free of oil.

Let us know please

Re: 2004 PT Cruiser Turbo rough idle [Re: moparjim79] #2990332
11/29/21 10:06 PM
11/29/21 10:06 PM
Joined: Jan 2003
Posts: 941
Klamath Falls, Oregon
Dartslantsix Offline OP
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Dartslantsix  Offline OP
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Joined: Jan 2003
Posts: 941
Klamath Falls, Oregon
Not much time to work when it's dark outside.
I was able to check a couple things: Motor mounts are good. Not much movement.
Sprayed the wires down in the dark and couldn't see any arcing.
Planning on pulling the plugs out this weekend and checking the gap. (didn't want to do it when the engine is warm)

Last edited by Dartslantsix; 11/29/21 10:15 PM. Reason: Detail
Re: 2004 PT Cruiser Turbo rough idle [Re: Dartslantsix] #2990353
11/29/21 11:17 PM
11/29/21 11:17 PM
Joined: Jan 2003
Posts: 31,961
Grand Prairie,Texas
stumpy Offline
I Win
stumpy  Offline
I Win

Joined: Jan 2003
Posts: 31,961
Grand Prairie,Texas
Check the turbo hoses to see if they are snug and not torn.

Re: 2004 PT Cruiser Turbo rough idle [Re: stumpy] #2990360
11/29/21 11:45 PM
11/29/21 11:45 PM
Joined: Jan 2003
Posts: 8,434
Freeport IL USA
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poorboy Offline
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poorboy  Offline
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Joined: Jan 2003
Posts: 8,434
Freeport IL USA
I have an 04 Turbo PT.
1) Replace the plugs and wires together. We do ours about every 50K miles.
2) Then, if you don't know the car's history, run some injector cleaner through the gas. We do that about once a year.
3) Inspecting the hoses is also a good idea. It gets hot under those hoods and the heat doesn't help old hoses, and that 04 PT is 18 years old.
4) Very little engine shake doesn't mean the engine mounts are still good. We had one set where the rubber crapped out and the bolts sat on the steel plate, very little engine movement, but it sure had a rough idle. You need to inspect each mount. The current engine mounts on our PT is the 3rd set at around 140K miles. As stated, replace them as a set. Gene

Re: 2004 PT Cruiser Turbo rough idle [Re: poorboy] #2990421
11/30/21 09:35 AM
11/30/21 09:35 AM
Joined: Mar 2003
Posts: 5,154
NEW JERSEY
AARCONV Offline
master
AARCONV  Offline
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Joined: Mar 2003
Posts: 5,154
NEW JERSEY
Do a compression test

Re: 2004 PT Cruiser Turbo rough idle [Re: AARCONV] #2990428
11/30/21 10:02 AM
11/30/21 10:02 AM
Joined: Jan 2003
Posts: 12,801
md
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mopars4ever Offline
I Live Here
mopars4ever  Offline
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md
Had rough idle on my 07 pt and it had a couple burnt valves. $1500 later it was fine.

Re: 2004 PT Cruiser Turbo rough idle [Re: mopars4ever] #2992095
12/04/21 08:11 PM
12/04/21 08:11 PM
Joined: Jan 2003
Posts: 941
Klamath Falls, Oregon
Dartslantsix Offline OP
super stock
Dartslantsix  Offline OP
super stock

Joined: Jan 2003
Posts: 941
Klamath Falls, Oregon
To conclude this thread-
It needed new plugs and wires. Car is running smooth now.
Thanks for everyone's help.

Re: 2004 PT Cruiser Turbo rough idle [Re: Dartslantsix] #2992205
12/05/21 10:44 AM
12/05/21 10:44 AM
Joined: Sep 2003
Posts: 15,320
north of coder
moparx Offline
"Butt Crack Bob"
moparx  Offline
"Butt Crack Bob"

Joined: Sep 2003
Posts: 15,320
north of coder
glad it was a relatively simple and inexpensive fix ! up
beer







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