Check engine light just came on

Tiny
NFULFORD
  • MEMBER
  • 2008 MERCURY MOUNTAINEER
  • V8
  • AWD
  • AUTOMATIC
  • 72,000 MILES
While driving on the highway the car will begin to buck. This usually happens when accelerating but also has happened while just driving. Check engine light just came on but quickly went off. Took it to garage but no computer codes came up. They told me could be something with transmission but they will have to take it apart to find out? Very hesitant. What else could it be?
Thursday, December 26th, 2013 AT 9:27 AM

52 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check fuel pressure with a gauge auto parts rent them and try cleaning throttle plate see link....

https://www.2carpros.com/articles/throttle-actuator-service

This guide will help as well

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
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Thursday, December 26th, 2013 AT 9:59 AM
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
I have repaired LOTS of vehicles for ignition misfire that were misdiagnosed as trans concerns over the years. Depending on how often it "bucks" it may not set a code right away but at the dealer level a tech can view mode 6 data history and see exactly which cylinder was missing if at all. I would get a second opinion from another shop.
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Thursday, December 26th, 2013 AT 9:39 PM
Tiny
JASACABEDA
  • MEMBER
  • 2 POSTS
  • 2008 MERCURY MOUNTAINEER
  • 65,000 MILES
At first I was getting a random tire monitor fault and sensor fault, then when the vehicle goes into drive the dome light wont shut off unless we wiggle the ignition. (And yes the dome switch is off) and now I'm getting check engine light which I got the code at o'reillys P0128 which says coolant low or bad fan or sensor. I had discount tires check the tires with a gadget that shows sensors working. All of these issues started up within a week of each other. So am I dealing with 3 different issues all possible sensors or a main computer unit?
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
No, the 128 is most likely a bad thermostat.

The tire pressure sensors are another separate unit. It can be checked with a scan tool from a shop to identify the sensor reading wrong. I assume you did check the tire pressures?

The dome light may be a bad switch and needs to be checked.

Roy
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
JASACABEDA
  • MEMBER
  • 2 POSTS
Fast and great response thank you!

Yeah discount tires used a tool and scanned each tire and said they sensors where working. He mentioned the pressure was a little high in each tire. He did ask if I was sure my rig was 2008 since his device was saying it was different.
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
A difference of 8 lbs and above will trigger the tpms light. I think you need another shop to check it for you.

Roy
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
WEEKSLM
  • MEMBER
  • 2 POSTS
  • 2007 MERCURY MOUNTAINEER
  • 122,000 MILES
My 2007 Mercury Mountaineer has been running a bit rough while accelerating, around 1500 to 2000 rpms. However, it runs perfectly when I manually turn the overdrive off. This morning, while accelerating on the highway, the engine light started to flash for about 30 seconds. I immediately took my foot off the gas and the light went out. It has not come back on, and I have been careful not to make any fast accelerations or stops. However, I am concerns about what the issue may be and how much it may end up costing me. Ugh!
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
PROAUTOTECH
  • MECHANIC
  • 288 POSTS
Scan it for codes

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
WEEKSLM
  • MEMBER
  • 2 POSTS
Well I was told it was misfiring on the 1st and 2nd cylinder. So they said I would need new sparkplugs first then possibly new coils. Does that sound right?
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
PROAUTOTECH
  • MECHANIC
  • 288 POSTS
Sounds right, do the plugs, the've probably never been done. Notice the gap difference between them and the new ones.
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
NIK EWOLDT
  • MEMBER
  • 1 POST
  • 2006 MERCURY MOUNTAINEER
  • 92,000 MILES
We took our 2006 Mercury into the shop when the check engine light come on and it started shaking they told us a mouse had chewed through the wires does this make any sense
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Yes it does mice, rats and squirles cause many$$$ in damage each year. Check with auto insurance they generally cover repair
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Monday, January 6th, 2020 AT 4:32 PM (Merged)
Tiny
ICPSCIENTIST
  • MEMBER
  • 3 POSTS
  • 2004 MERCURY MOUNTAINEER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
Yesterday the car started fine, but died when put into gear. I pulled the battery and had it checked; it came back as "bad".
I got a new battery (higher CCA than previous one) and installed it. Now, the engine either won't start (it cranks but never catches), or it does start but runs very rough and almost right away the dashboard message center tells me the engine is running in "Failsafe" mode.
I am positive that I have good, strong connections at both battery terminals and I've ensured that I have proper engine coolant level (the vehicle owner's manual mentioned this may be a reason for running in "Failsafe").
Any thoughts? Thanks.
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
DOCHAGERTY
  • MECHANIC
  • 9,603 POSTS
Scanning the car through the OBDII port for currently present faults is going to be my recomendation to you mate. Do that and repost with the outcome please.
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
VENUS55564
  • MEMBER
  • 1 POST
  • 2004 MERCURY MOUNTAINEER
Shakes or Wobbles problem
2004 Mercury Mountaineer 6 cyl All Wheel Drive Automatic

my truck has a shake when turned on and or when accelerating. I checked the plugs and wire. They appear fine. What causes a shake on this truck? Engine light is also on. Does the amount oil in truck cause it to shake?

Many thanks,
venus
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Have the computer scanned for code/s-you have a problem within the engine management system that caused the CEL to turn on-This is your starting point of diagnosis, finding out what's going on.
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
JTELLEZ
  • MEMBER
  • 1 POST
  • 2003 MERCURY MOUNTAINEER
2003 Mercury Mountaineer V8 All Wheel Drive Automatic

My suv feels shaky when it's in the drive position and I am stopped at a stop light. When I go 50mph or over it starts to shake even more. The check engine light was blinking on and off but not any more. Can someone tell me what this might be.
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
You probably have a misfire. There is fuel that is not being burned and getting into the cat. The cat can ignite the fuel and heat it up to much and break it down.

IF the the light flashes, the chance of damage increases dramatically. You can kill the cat by continueing to drive like this.

You need to get the codes from the computer to begin diagnosing this.
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
RYCE
  • MEMBER
  • 1 POST
  • 2003 MERCURY MOUNTAINEER
  • V8
  • 4WD
  • AUTOMATIC
  • 157,690 MILES
What does it mean when my check engine light is blinking and two codes come up. Codes p0307 and p0430
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Monday, January 6th, 2020 AT 4:33 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
307 means number seven cylinder is missing and 430 means the right catalytic converter is clogged or no longer working. The misfire can be anything from a basic problem to injectors, or sensors and best to have a mechanic fix these so you do not waste money on parts that are good.
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Monday, January 6th, 2020 AT 4:33 PM (Merged)

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