Have a random misfire on a 2009 VCT motor 5.7 hemi 1500 Laramie. Spent today putting 16 plugs in that big bitch.
Here's the catch, when I'm getting the misfire, i can pull over, cycle the key a couple times without starting, then start it up and the miss is gone. It only happens when it's been sitting for a bit or on a morning start up.
Any ideas on what to hit next. I don't want to throw parts into it blindly.
186K primarily highway miles, no drop in mileage, engine temp, oil temp, oil pressure, or trans temp. 7200 hours on motor. Any suggestions welcome.
Update: 3/12
Bad roller lifter took out camshaft. When I first noticed a tick I slapped a giant welding magnet on the oil pan and left it there which down the road was a very fortunate thing. The shop got into the motor, replaced cam, lifters, timing set and did plugs and valve seals since we weren't going to get any closer. The mds actuators apparently have small magnets in them and they attracted metal shavings and obviously were replaced with plugs included in the MDS delete portion of the kit. The cam bearings themselves were as you would expect for an engine with this many miles, no gouges or scrapes and still smooth.
They went ahead and pulled the pan to check for debris. My magnet had attracted a metric shit ton of metal shavings but having that magnet on the pan kept the shavings from plugging up the pickup screen and oil starving the engine. Oil pump was replaced and they flushed the passage from pump to pickup and pump to filter and both came clean. It appears the filter and everything else did its job.
The shop also popped off a main cap and rod cap. They also looked good.
I really think the MDS delete has helped the drive-ability immensely. Better throttle response and the trans doesn't hunt and peck for gear driving around town anymore.
The power is the same or better and the fuel economy as a whole is equal or better. I'm getting roughly 18.0 mpg at 65mph for last 1k miles and was getting 16.8 previously over about 100k miles. Stop and go I'm around 14/15mpg and was around 12/13 mpg before, so Im getting around 440 miles a tank currently instead of the normal 400/425.
Total cost ended up just under $3k and while it hurts the pocketbook, it just needed to be done.