Zuiun
New Member
- Joined
- January 22, 2015
- Messages
- 5
- Reaction score
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- City, State
- Lincoln, Nebraska
- Year, Model & Trim Level
- 1999 Mercury Mountaineer
Warning: Long so as to provide as much detail as possible...
I have a 1999 Mercury Mountaineer 5.0 V8. It has approximately 135k miles on it. I purchased it at 50k. It's been regularly maintained.
I live in Nebraska and take 2 (or more) trips a year to Colorado Springs to visit family (an elevation change from about 1,100 feet to 6,000+ feet).
I've never had issues until the last two trips.
First incident: Trip up to CO was fine with zero issues. On the trip back, it was approximately a 95 degree day and heading from Co. Springs through Brush, Colorado, I begin experiencing engine hesitations that feel like I'm running out of gas -- tank is just under 3/4 full. Before I can make it all the way into Brush, the truck throws a "check engine light."
My first thought is "vapor lock." My second thought is "that shouldn't happen on this engine."
Regardless, I stop in Brush for the night and have the code check the next morning at a local shop. The code reads lean on bank 1 and 2. They check it over and find nothing wrong. They also conclude vapor lock. Since they engine has cooled down and it's a cooler day, they feel it should be good to go.
Sure enough, I make it back to Nebraska with zero problems.
Drive the truck during infamously hot days (99+) throughout Nebraska, again with zero problems.
Flash forward to the next trip to Colorado this past weekend. Again, a very warm day (90's+). About half way into the trip (both distance and altitude)... same hesitation problem, check engine light again. This time near a small town that happens to have an open Ford dealership.
Same engine codes.
They check the codes, recommend a fuel injector cleaner and changing the fuel filter. Stay the night and continue to Co. Springs the next morning.
No issues until about 15 miles out from the Springs. Same hesitation again... only this time, I suddenly get a complete momentary loss of power, RPMs drop and it feels like the engine is going to die. I'm just hoping I have enough momentum to get to the side of the road... then one last "sputter" and then nothing. And by "nothing," I mean the engine smooths out, RPMs return to normal, and zero hesitations the rest of the way into the Springs.
I have a mechanic look it over and he finds nothing obviously wrong and since that last instance didn't trip the check engine light, there were no codes to find.
Truck continues to drive like a champ while in the Springs.
Nervously, I drive back to Nebraska, but there are absolutely zero problems on the trip back. Not one single hiccup.
But I'm not exactly willing to accept that the truck just magically fixed itself. So...
1. Vapor lock. If that's the problem, is that even possible with these engines? (1999 Mountaineer 5.0 V8) Where would I begin to trouble shoot this, especially given that it's now running fine and only seems to develop an issue at altitude when it's unusually warm?
2. Blockage. Is it possible there was some kind of blockage that blew itself out? If so, any theories about why it would only surface during the combination of high altitude and hot days?
3. ??? What other options should I be looking at?
Thanks in advance for reading and any advice.
I have a 1999 Mercury Mountaineer 5.0 V8. It has approximately 135k miles on it. I purchased it at 50k. It's been regularly maintained.
I live in Nebraska and take 2 (or more) trips a year to Colorado Springs to visit family (an elevation change from about 1,100 feet to 6,000+ feet).
I've never had issues until the last two trips.
First incident: Trip up to CO was fine with zero issues. On the trip back, it was approximately a 95 degree day and heading from Co. Springs through Brush, Colorado, I begin experiencing engine hesitations that feel like I'm running out of gas -- tank is just under 3/4 full. Before I can make it all the way into Brush, the truck throws a "check engine light."
My first thought is "vapor lock." My second thought is "that shouldn't happen on this engine."
Regardless, I stop in Brush for the night and have the code check the next morning at a local shop. The code reads lean on bank 1 and 2. They check it over and find nothing wrong. They also conclude vapor lock. Since they engine has cooled down and it's a cooler day, they feel it should be good to go.
Sure enough, I make it back to Nebraska with zero problems.
Drive the truck during infamously hot days (99+) throughout Nebraska, again with zero problems.
Flash forward to the next trip to Colorado this past weekend. Again, a very warm day (90's+). About half way into the trip (both distance and altitude)... same hesitation problem, check engine light again. This time near a small town that happens to have an open Ford dealership.
Same engine codes.
They check the codes, recommend a fuel injector cleaner and changing the fuel filter. Stay the night and continue to Co. Springs the next morning.
No issues until about 15 miles out from the Springs. Same hesitation again... only this time, I suddenly get a complete momentary loss of power, RPMs drop and it feels like the engine is going to die. I'm just hoping I have enough momentum to get to the side of the road... then one last "sputter" and then nothing. And by "nothing," I mean the engine smooths out, RPMs return to normal, and zero hesitations the rest of the way into the Springs.
I have a mechanic look it over and he finds nothing obviously wrong and since that last instance didn't trip the check engine light, there were no codes to find.
Truck continues to drive like a champ while in the Springs.
Nervously, I drive back to Nebraska, but there are absolutely zero problems on the trip back. Not one single hiccup.
But I'm not exactly willing to accept that the truck just magically fixed itself. So...
1. Vapor lock. If that's the problem, is that even possible with these engines? (1999 Mountaineer 5.0 V8) Where would I begin to trouble shoot this, especially given that it's now running fine and only seems to develop an issue at altitude when it's unusually warm?
2. Blockage. Is it possible there was some kind of blockage that blew itself out? If so, any theories about why it would only surface during the combination of high altitude and hot days?
3. ??? What other options should I be looking at?
Thanks in advance for reading and any advice.
