If it's JUST misfiring on cylinders 5 and 3, run a compression test.
If the compression is down you'll need to remove the heads and inspect for damage or worn valves.
Since you didn't specify what kind of engine, I can only assume either a V6 or V8, and many "V" configuration engines have all even cylinders on one side and odd on the other.
If I can make an assumption, I would assume that the cylinders that are misfiring are adjacent to each other, giving a little more concern that it might be a failed head-gasket, but you won't know until the head is removed.
But again, check the compression first.
If compression is up across all cylinders, focus on electrical. Some engines used "coil packs" which caused a single coil to fire two cylinders. If that's the case you could have a problem with the coil pack or the electronics that fire it.
On a Ford Windstar , V6 engine : firewall 1-----2-----3 4-----5-----6 front of vehicle > driver
On a 2001 Ford Windstar : firewall 1-----2-----3 4-----5-----6 front of vehicle > driver
Start by replacing all the spark plugs. If that does not solve the problem then replace the spark plug wires.
Defective spark plug or plug wire. Can also be blown head gasket or burnt valve.
start with wires
Each cylinder needs fuel, compression and spark. You are missing one of those.
firewall 4 - 8 3 - 7 2 - 6 1 - 5 front
Kiya Fix is 5' 3".
Depends on the transmission and year. 5 or 6 cylinder? What is the problem with the transmission?
A cylinder with a radius of 5 units and a height of 3 units has a volume of 235.62 units3
the number 5 cylinder is the rear cylinder on the driver side 6 5 <---cylinder diagram 4 3 2 1 front of engine
Find and repair the cause of a misfire on cylinder #5.see related question below.Find and repair the cause of a misfire on cylinder #5.see related question below.