Engine Decarbonization??

[coolvirus]

Hi. It's been a while since I posted here.

I have an 03 PT GT with 31,000 on it. About a week ago I noticed the car was vibrating at idle (haven't noticed it when driving).

I took the car to the dealer today and they recommended an engine decarbonization to remove carbon buildup and as a result of that procedure, the spark plugs would need to be replaced as well. Cost of repair: $464.

Or they also recommended a more complete tune up for $550. I told them I'd think about it and got my car out of there. The cost seems excesive to me and it doesn't look like they were sure that this would fix the problem.

My questions are:

1. Any idea what could be causing this vibration?
2. Has anyone gotten this engine decarbonization procedure?
3. Would carbon buildup cause the vibration and if so, how?

Thank you in advance guys.

[rszappa1]

A total rip-off on the Engine Decarb....

[sca037]

If carbon buildup is truly the problem, you can address it yourself quite easily.
Grab an empty spray bottle and fill it with clean water. Remove the hose from the front of the throttle body, and remove the cover over the throttle cable where it attaches to the throttle body. Start the car and let it warm up for a minute then while opening the throttle, spray a little water into the TB. Make it a fine mist, and do not give it so much that the engine wants to stall. This process will lightly steam clean the valves and the tops of the pistons, allowing any carbon to exit out the exhaust.
If this doesn't improve the idle quality, add some Chevron Techron fuel injection cleaner to your tank to be sure the injectors are clean.
New plugs and wires can have a major effect on smoothness at all rpm's
If you still have a bit of roughness in the idle after all that, then all I can say is "welcome to the club" ;^J

Brian

[coolvirus]

Hmmm, I'm not mechanically inclined at all and even though that might be a simple procedure for others with experience, I wouldn't even want to attempt it. Thanks for the suggestion though.

A fuel injector cleaner in the tank sounds a lot easier. Maybe I'll give that a try.

My concern here is, sure changing spark plugs and wires would help with the rough idle, but shouldn't these components last longer than 31,000 miles?

I don't have my PT Cruiser manual in front of me. Does anyone know how often (mileage) Chrysler recommends that the spark plugs be replaced?

[PT2NV]

Didn't have the manual in front of me, either but I looked it up

Pages 275 - 278
Schedule "A" - 2.4L TurboCharged Engines
Replace plugs every 30,000
Replace plug wires every 60,000

[coolvirus]

He, he...touche PT2NV. May I ask where you found the manual? I'll try to look it up as well.

So it seems that it is time to change the plugs. Wow, I thought they would last a lot longer than 30K miles.

[Red GT]

coolvirus, I had all of the above done, plus a whole lot more at 30,000.(for 30,000 service) Tune-up pluges ,wires,decarbonization, front brakes,with brake flush, oil change, tires rotated, with Road Force balancing ,replace the air filter. Had the works. Now I gotta tell ya my car has never run better, and has never had better gas mileage either. I also have a '03 GT. So, the vibrating at idle thing I'm not sure why they'd want to do these things for that. But you are due for the 30,000 service. I just took my car in to have the brakes looked at because they were making noise and it turned out they were fine, just dust. (live in the desert) But, they noticed that it was shaking at idle or (vibrating) looked at it and discovered it needed motor mounts. I have 38,700 miles on mine. So, there's a thought. Luckily I have an extended warranty so it didn't cost me a thing. Motor mounts $1,000!! The dealer you went to does sound really high. Tune up with plugs and wires for me was $135. The decarbonization was $177. Now some of the things I had done were not part of the 30,000 service and I still got off cheaper than you would at this dealer for this vibration problem you have. And all they're doing is a 30,000 service, don't go to them. Try another dealer.

[bobs turbo pt]

sems expensive !! shop around !!

[purple04]

Wipe the word SUCKER off your forehead and go somewhere else.
The decarbonization is a good product, but they are charging too much. Take the car to a shop you can trust and have them do the plugs and wires. The wires are known to be weak, and the effort to replace them when doing the plugs is minimal. Ask them what they charge for a top end clean or decarbonization. Shouldn't be more than $85 retail. It should include a couple things. First, cleaning the throttle body. This takes care of some idle issues. Second, a chemical that is run while in the shop. This will start the process of cleaning, and should help the next day's cold start. Third, a chemical in the tank. This completes the process by slowly cleaning the rest of the junk in the top end. The car should get smoother over the next few days. And yes, the Techron you get at the store is the stuff that is put in the tank.

[Mean Green]

"Motor mounts $1,000!!"

Please tell me you are kidding. I can get filled motor mounts (for high hp PT Turbo's/SRT-4's) for $70 a piece. It's 1-1 1/2 hours to install both upper and lower motor mounts and that's taking my time.