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Dan, Technician
Category: Lincoln
Satisfied Customers: 24009
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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Kenny i have a 2004 lincoln navigator with the 5.4 liter

Customer Question

hello kenny i have a 2004 lincoln navigator with the 5.4 liter motor it has a rough idle with stalling occassionally i had it checked and the mechanic couldnt find anything wrong he changed the plugs and checked everything both mechanical and electrical and he said one side of the motor is running rich and the other side is too lean please help
Submitted: 1 year ago.
Category: Lincoln
Expert:  Dan replied 1 year ago.

Hello, my name is***** check engine light ever come on? Thanks.

Customer: replied 1 year ago.
Expert:  Dan replied 1 year ago.

Has anything been replaced? Thanks.

Customer: replied 1 year ago.
Plugs were replaced
Expert:  Dan replied 1 year ago.

This usually means you have a dirty throttle body if vehicle runs good otherwise. A failing coil can cause stalling but will also cause misfire which usually turns on check engine light. You can get throttle body cleaner from your local parts store, spray onto rag, and wipe out throttle body good. This is so simple it is often over looked, a shop would charge around $60. Let me know if you have more questions or if there is anything else I can do to help. Thanks.

Customer: replied 1 year ago.
Throttle body was cleaned he claims that one side of engine is running lean and the other is too rich
Expert:  Dan replied 1 year ago.

That would usually turn on the check engine light. A misfire could make one side run lean/rich so that could be something took into. Another possibility would be injectors. Any idea how they determined one side is running rich and other lean?

Customer: replied 1 year ago.
The mechanic checked all coils and said exhaust might be restricted but then he created good flow and motor is still idling rough
Expert:  Dan replied 1 year ago.

I'm starting to think mechanic is not doing proper testing or have correct equipment. I would recommend bringing to a different shop, even dealership. I do not think this is a serious problem and is somethin the dealer can fix within a hour of labor. Let me know if you have more questions, thanks.

Customer: replied 1 year ago.
I didn't pay for you to tell me take it to another shop
Customer: replied 1 year ago.
If that's your best answer I want a refund
Expert:  Dan replied 1 year ago.

I can put in refund request or open question up to see if someone else has some advice. I'm just not sure your mechanic has properly cleaned throttle body or determined vehicle is running rich/lean properly. Somethings are hard to figure out over computer, especially if you are no doing the work yourself so I'm talking 3rd person. Let me know if you would like refund or me to open question back up. Thanks.

Customer: replied 1 year ago.
I'm a car dealer and sort of knowledgeable with cars and my mechanic is excellent and he even sent it to a automotive electrical expert and it has them stumped it has good compression and everything checks out could it be a intake manifold gasket or a vacuum leak or catalytic converters
Expert:  Dan replied 1 year ago.

I think problem is dirty throttle body or throttle body itself. A vacuum leak should show up when spraying gaskets with starting fluid. Catalytic converter would not cause this symptom either. Most vacuum leaks would also set lean codes.

Customer: replied 1 year ago.
It has a rough idle and stalls on occasion the throttle body was checked as well please just refund my money