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Amedee
Amedee, Jeep Technician
Category: Jeep
Satisfied Customers: 26604
Experience:  ASE certified Technician advanced level specialist. Wisconsin certified emissions state inspector
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It is sputtering when I accelerate. It happens when I press

Customer Question

It is sputtering when I accelerate. It happens when I press the gas more than 1/4 of the way. Usually goes away above 3500rpm. I've changed a ton of stuff and am lost.
JA: Has the vehicle turned into a gas hog? And how does it start -- same as usual?
Customer: Same
JA: What is the model/year of your Jeep?
Customer: 1995 Wrangler 2.5L
JA: Are you fixing your Wrangler yourself? What have you tried so far?
Customer: Yes.
JA: Anything else you want the mechanic to know before I connect you?
Customer: I've tried a ton of stuff
Submitted: 1 year ago.
Category: Jeep
Expert:  Amedee replied 1 year ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  Amedee replied 1 year ago.

Can you start by sending me a list of things you have replaced up to this point?

Also, any stored codes in the computer and your VIN would be helpful too!

Thank you!

Customer: replied 1 year ago.
I have replaced/checked the following:Oil & filter
Fuel filter
Spark plugs
Plug wires
Distributor cap
Distributor
Rotor
Coil
TPS
O2 Sensor
Fuel injectors
Fuel pressure
New gas
Sea foam
Cleaned throttle bodyI am getting codes:12
33
21
41
55
Expert:  Amedee replied 1 year ago.

Thank you for that information. Was the crankshaft position sensor replaced?

Customer: replied 1 year ago.
I don't believe so, no
Expert:  Amedee replied 1 year ago.

Ok, if you clear all codes, which code comes back first?

Customer: replied 1 year ago.
I've done this a few times, 21 is the code that keeps coming back. Other than 12, 33, & 55 which I don't believe are the problem
Expert:  Amedee replied 1 year ago.

Do you know what the distributor sync or indexing is set at?

Customer: replied 1 year ago.
No.
Expert:  Amedee replied 1 year ago.

Have you checked for plugged exhaust?

Customer: replied 1 year ago.
the catalytic converter is good
Expert:  Amedee replied 1 year ago.

What is the exhaust back pressure at?

Expert:  Amedee replied 1 year ago.

How about the engine vacuum?

Customer: replied 1 year ago.
Not sure about either
Expert:  Amedee replied 1 year ago.

Ok, no problem. Sounds like we have several things to check. First, lets start by checking the distributor indexing. This is very important that it is set correctly. To do this, bring the engine to Top Dead Center number one cylinder and remove the distributor cap and check the position of the rotor tip to the distributor cap tower. If it is indexed correctly, the rotor tip should be leaving the number one tower, on its way to the next cylinder on the cap, 0.020 inch away from the number one tower. If needed, loosen the distributor hold-down and adjust. The hold-down may need to be modified in order to make this adjustment.

The exhaust back pressure should be no more than 1.5 psi at 2500 rpm. Just because the converter is not plugged up does not mean the muffler is not plugged. I have seen it many times before.

Also, the engine vacuum is a very important test. This will tell us if the engine is breathing good. Maybe we have a loose or jumped timing chain. Late valve timing or even an intake restriction. This will all lead to poor engine breathing issues which will show up on a vacuum gauge. It should be approximately 19 inches of solid steady engine vacuum at idle.

I am glad I can help!

It has been a pleasure working with you. Please dont forget to honor your good faith deposit by rating my answer as "5 STAR SERVICE" for assisting you today.

Please let me know if you have any further questions.

Expert:  Amedee replied 1 year ago.

Hello! It'sCustomerfrom just answer.

I am just checking in to see if you need any further assistance?

Let me know!