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So I recently acquired a one owner expedition with the stupid 4.6 in it. Has about 150k miles and is in need of some tlc. However I don’t want to put any money into it until I can get the misfire out of it.
No cel codes except for the o2 sensors due to not having both cats on it. “Someone stole one” I’ll fix that later. It has a weird misfire that I can’t pinpoint. It’s three or four cylinders and I’ve got spark from both coils, if I unplug either coil nothing changes haven’t pulled them out but my scan tool is telling me the injectors are all firing and on the cylinders that are missing the plugs smell like gas. I am going to replace the plugs and do a compression test on all cylinders. I noticed one of the coils was firing orange so I replaced that with a known good one. I was thinking it was an intake gasket problem but sprayed carb cleaner around the base of all the intake runners and couldn’t find anything.
Any advice is greatly appreciated. I’ve got roughly two months to get this thing going before snow so I don’t have to drive the camaro
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If you unplug a coil and don’t hear/feel a difference then that cylinder is definitely misfiring. If they’re independent coils instead of wires coming from a single coil then swap them into a cylinder that you know is firing and see if the misfire moves to a new cylinder. If the problem persists then do the same with the spark plugs (or just replace them all, but it depends on your budget). If this still doesn’t fix the issue then you’re down to either a fuel or compression issue. Personally, I would start with a compression test because it’s probably easier than removing the fuel rail and swapping injectors around. Plus, if it’s cylinders 3 and 4, it could be a head gasket issue where the gasket failed between those two cylinders. Check your oil and your antifreeze to see if they’re mixing together, and also check for blue or white smoke from the exhaust. My “poor man’s” compression test to see if there is a total loss of compression in one or two cylinders is to remove all of the coils and crank the engine for a few seconds. If you can hear hops or skips in the cranking of the engine, they can lead you to a compression issue, but to know for sure it is always better to just rent/buy/borrow a compression tool, or even better yet, a leak down detector to see if the rings could be bad (Eric The Car Guy actually has videos on all of these procedures if I recall correctly). If your compression test checks out OK then you’re left with a fuel issue. This is what I had to deal with when I replaced my engine, as it came with a bad injector, and I ended up having to pull the whole rail out. Even on my four cylinder it took me a good hour or more to fight that thing out of there and get the new injectors oriented correctly and bolted back down, and I can imagine that it won’t be much easier on a V8. However, if you can manage to gain easy access to them in such a way that you can also run the engine, you may be able to run it and feel each injector to see if it’s firing. If not, you may have to employ the same method as with the spark plugs/coils and swap them around to see if the misfire moves to a different cylinder.
I hope all of this nonsense helps a bit. If anybody else has some other ideas that are more familiar with these engines please feel free to correct me. I’m a Honda owner and there are definitely some differences between the two.
Thanks for the advice!
It’s is three or four of the cylinders that are missing. This particular engine has two coil packs each feeding four cylinders. The thing that stumps me is if I unplug the drivers side coil there is no change. So then I unplug the passenger side coil after plugging the other one in and still no change. I just found some info on these coil packs and how to check and see if they are getting the right signals from the ecu. I will try and get a video posted of how it currently runs. The gas in the oil is making me think is a compression or ignition problem. I’m going to try and track down a compression tester for now. Budget is kinda tight right now my camaro is soaking me dry, new steering column “not cheap”. If I can get a video I will link it in a post.
However it does seem to shake and miss on startup almost like the 3.0 eclipse that my friend has that we just had to put four valves in due to a broken timing belt. The original owner said he’s never had the timing system serviced and now I’m wondering if the chain slipped!
I would like to apologize in advance for spelling and such! For some reason my phone isn’t letting me see what I’m typing so I can’t fix anything. Using autocorrect and hopping for the best!
Some more info I forgot to add, the vehicle currently does not have an accessory belt on it. It was parked when it started skipping and sat for a couple years. When I first went to look at it we thought the engine was seized ended up being the alternator. I just found out yesterday that there is no fuel cap on it. Just a plastic bag shoved in the filled neck I drained the gas and put five gallons of fresh gas in thinking water was the culprit. That made no changes except it starts a little easier now. I also added a fair amount of drygas to try and rid any moisture from the system. Gauge cluster has an intermittent problem where the mileage will not illuminate ” I had no idea of the miles until just the other day and I’ve owned it for almost a year.
Previous owner said it has new wires and plugs, wires look new plugs not so much. One coil pack is new the other came off an escort I’ve got same PN and that car ran fine. Injectors look very rusty but as stated before my scan tool is telling me they are all opening fine. I have 55~62 psi of fuel pressure “crappy gauge”. When I learn more I will post.
Really hoping to get this fixed I live in upstate NY and don’t want to drive a camaro this winter.
I may give up and get an hour of diag at the local Ford dealer
On the 4.6 you should be able to disconnect the coils by the pigtale without takeing the coil out… do one at a time..if theres no noticable diffrence change the coil.. and while yur there may as well change the plug
From my experience, chasing bad coils is a huge pain. I did it for a couple years and it will cause so many headaches. For my year, I have one coil per plug. Coils are expensive at part stores, $50-60each. Go to Rock Auto, they run $10-30each, buy 8 and be done with it. However, I think your year has two 4 pack coils. Still, just replace them both and be done with the chase game. Plugs and the plug wires while you’re at it. At Rock Auto, I think you’re looking at over $100 to do the whole job, and it’s better than a whole bottle of aspirin for the headache. Get a Haynes if you don’t have one, very helpful to know firing sequence and ignition coil positions. Also careful to match up plug wires by length to the ones they’re replacing. That last bit was a hard lesson from an attempt when I was 20. It sucks when you mess plug wires up.
I did this with both trucks, and I couldn’t be happier with the results.
I am definitely going to replace plugs and wires. And if the budget allows it both coils. But I’m going to do a compression test first. I have great fire at all plugs now but I have seen it change when you add compression to the plugs.
I most likely just landed a new job and will be almost doubling my salary. If that happens I’m just going to either part out or sell it and buy a newish car or truck. Found a really nice ram 2500 diesel with a manual trans that I really want.
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