How many miles on the vehicle?
The PCM picks up misfires by noticing a change in the crankshaft speed. If one cylinder fails to fire and burn correctly, it will NOT give the push to the crank that it should and the crank will slow down slightly until the next cylinder fires correctly.
So just about anything that would cause less than perfect burning in that cylinder can cause a misfire.
Spark Plugs are a common one, and you should catch up with any overdue maintenance for the engine. Check the O.M. how often should your plugs be changed? Most 3.7L, its every 30k miles, if you're overdue for a plug change the plugs could be eroded away and NOT making a good spark and often does cause misfires.
Ignition wires do deteriorate over time and with use earlier 3.7L had a coil per each plug, so you just have to inspect the boots and makes sure they are still good, later 3.7L had a wasted spark system, with coils on half the cylinder and a spark plug cable going to the other cylinder. If one of those cables are bad, that could cause misfires.
Air filter, unlikely, it would have to be incredibly clogged to cause misfires, but if the air filter has never been changed on your vehicle its possible its that clogged.
Dirty or fouled fuel injectors can cause misfires.
Bad fuel or water in the fuel can cause misfires.
Try some fuel injector/gas treatment, Chevron Techron is the best cleaner IMO and the only one recommended by Chrysler.
Vacuum leaks can cause misfires, check all your hoses and the intake manifold and throttle body. The MAP sensor measures the vacuum in the manifold, so if the vacuum was off in the manifold, that could be throwing off the MAP sensor and causing the P1052 code you're getting.
The 3.7L intake manifold is bolted down with most of its bolts also being the coil pack bolts, so if one or more coil pack was removed to change plugs and then not torqued down correctly, it might cause a leak in the intake manifold, perhaps causing your problems.
Finally, I had a P0302, which is a misfire in the #2 cylinder. I checked and tried everything and it kept coming back. I finally figured out it was the seals on the plastic intake manifold that were leaking. When I replaced the seals it solved the misfires and the engine ran much smoother and got better mileage. Unfortunately, since the engine compartment is so cramped, it takes a ton of work to get the intake manifold out to replace the $10 worth of seals. Took me a day and half to do it. If you're going to pay a shop to do it, the labor will be a lot.
I had a 130k miles on my motor when I replaced the seals, from what I saw it looks like it would be a common thing on higher mileage motors.
One thing I did to identify it was the seals on the intake manifold, since everything I tried before this didn't work. Was to tighten down the intake manifold bolts a little more than they were, that improved the situation greatly, sprayed a little oil into the gap between intake manifold and head, where the seal was leaking, that solved the situation totally. But that oil filling the leak would last a few days, so I got all new seals.
And one last thing I learned, in case this turns out to be your problem. Its a lot of extra work to make the room to get the intake manifold out completely. BUT, you don't need to get the intake manifold out completely to replace the seals, you can probably do the job in half the time, if you just unbolt what is necessary to raise the intake manifold and pull out the seals and put in the new ones, wipe the surfaces clean with a rag.
Since its a plastic intake manifold it uses a different kind of seal, it doesn't bake on and you just need to wipe the surface down with a rag to clean it.
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Last edited by Mongo; 05-19-2016 at 01:51 PM.