2007 Mercury Mountaineer misfires

Anyone else having misfire issues, I get getting check engine lights and when I scan the vehicle I get misfires code errors on multiple cylinders, changed the spark plugs and coil packs still getting the error code and check engine light

Given that you’ve replaced plugs and coils, the problem is unlikely to be in either. There could be a bad crankshaft position sensor or it could be fuel related as in leaking injectors or a vacuum leak. However, I’m not a mechanic so those are mostly guesses.

Does this engine need valve lash adjustment? How well has the oil change regime been followed?

i know this is a different car, but i had a windstar with the same problem. it turned out being… on the side of the throttle body there are 2 linkages with plastic bushings on them that broke causing the linkage to pop out. the linkages go to the intake manifold runner control valves. [ butterflies]. I replaced the plastic bushings and no more misfire codes.

I have it tested for vacuum leaks and compression and both turned out to be fine.

I change my oil around every 5000 miles or whenever the oil indicator comes on. dont know what a valve lash adjustment is but i’ll google it. Thanks.

Thanks for following up. But you haven’t ruled out bad injectors or crankshaft position sensor. Did the shop that tested for compression and vacuum leaks suggest anything? Best of luck finding the solution.

Interesting that you have never told us what engine you have, nor how many miles are on it. You have also never posted the codes you read.

Plus you took it to someone who could do a compression test and a vacuum test and did not post the results. Why didn’t this person also try and diagnose the misfire?

Finally, how are we supposed to help you with this problem misfire without any actual data? By consulting our crystal balls?

The ford dealership pretty much told me they tested everything, even swapped out glow plugs, etc. Still cant find whats causing the problem, they told me it might be electrical but im not paying german mechanics double what id pay an american mechanic. I had a guy with the same vehicle as I ran into at a gas station he told me he had the same problem with the 4.6L we have and he had to change the EMC. Im to the point where Im about to junk this piece of crap and get me a range rover from england like I had 10 years ago.

4.6l, 156,000km, codes 300, 301 and no I wasnt expecting you to use your crystal ball. I thought you’d use your Ouji board…

A Range Rover better be new with a warranty or you will really be upset. This is mostly a US site and it appears you are not in the US so repair prices are what they are where you are.

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Trust me I know, this isnt my rodeo overseas, I always order most of my parts from the states when possible, although as a service member we get 19% off most stuff on the economy so some things are actually cheaper here, like rotors and brake parts.

You don’t have glow plugs, you have spark plugs.

If they tested “everything” they would have found the problem.

So a general mis-fire and a specific mis-fire on cylinder #1. That’s all?

You said a compression test was done… but did not post the figures and my Ouji board is in the shop for its 20,000 prediction service so if #1 is low, that might be your problem right there. That is a guess, which is all I have to go on.

I’d be looking at scans of the engine while running to see if there are any hints in long term fuel trims for bank 1 compared to bank 2 as well as for lazy O2 sensors, leaky injectors or lazy injectors. Might try swapping injectors between cylinder 1 and another on bank 2 to see if the mis-fire follows. Maybe Ford did this, I don’t know, you don’t say. Maybe Ford checked “everything” they were willing to check for you, but not everything they could. We’ll never know.

Then it is time to cut your losses and sell or scrap the vehicle.

Good Luck with that Range Rover. From what I read about their quality, you are surely going to need it.

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In their annual owner survey regarding vehicle reliability, Consumer Reports consistently ranks Land Rover/Range Rover as the worst of all makes. When a car company ranks even lower than Fiat, that is indicative of major problems.

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