My 2000 Ford Ranger 4.0 OHV is having an issue, I know its not bad gas etc, it cranks a little rough at first but stops idling rough after a few seconds, then when I start down the road and it usually happens when I don't get on the throttle much, it'll start misfiring pretty bad but if I put the throttle to the floor it will stop, its not throwing any codes, I'm thinking its a vacuum leak somewhere but I have no clue, if someone can help thank you.

 

do you have cruise control

 

Welcome to the forum

Warm up engine
On the front, side, of upper intake is the IAC(idle air control) valve it has 2 wires plugged in to it.
While engine is idling(warm) unplug those wires, RPMs should drop to 500, or engine may even stall, either is GOOD, it means no vacuum leaks.
If idle is above 700 then there is a leak
Start unplugging vacuum hoses from intake and seal port with finger, when RPMs drop you found the hose with the leak.
If all hoses are OK then you will need to check intake gaskets.

Vacuum leak almost always causes a lean code

 

good advice from ron

several reports i read about almost always result from vacuum leaking from the cruise control vacuum bulb

mounted behind the front passenger side inner fender cover

 

Thanks for the reply, I read a little more and browsed me and my dad checked for vacuum leaks and their fine, so I read more about my issue cause its not throwing any codes, I read that the closest thing to my issue is a cracked cylinder head.

 

4.0l OHV did have a weak spot between valve seats in the heads that could cause a crack if overheated.

But symptoms of that problem would also include a full overflow tank from too much pressure in cooling system and overheating if driven more than 15 minutes.

Misfire would be a secondary symptom

 

RON he has the SOHC 4.0L engine

 

2000 Ranger = 4.0l OHV, 4.0l SOHC started in 2001 model year

Explorers started getting 4.0l SOHC in 1997 as an option, but could still have the OHV until 2000 model year