Good Morning,

I'm a new member with this web-site. Having said that, this is the issue that I'm having with the truck that I just recently obtain.

I have a 2004 Ranger 3.0 v-6 engine; the issue that I'm going through is when ever I'm in traffic the engine stalls on me, (check engine light on) and I have to keep it at high idle by keeping my left foot on the brake, and right foot on the gas in order to keep the RPM's high. I took it to Auto Zone and I was told that the # 4 and # 6 cylinder was not firing then I was told that the # 5 and # 6 cylinder was not firing, and that it was best to do a complete Tune-up by changing spark plugs, coil, and cables (I did it) problem still exist. I've change air filter, the PCV valve, and one of the air sensors that go's right before the gas injector area. The other thing I was told to look for is a vacuum leak. I forgot to mention that the truck has over 2 hundred thousand mile. It still runs good except for the issue that I just mention, and only when engine starts to warm up, and not cold. Can anyone help me with this issue. Help.

Bruno Ranger

 

Welcome to the forum

Yes, its possible to have a vacuum leak cause stalling but..............it usually causes HIGHER rpms at idle not lower

Fuel injected engines can't use an idle screw, no Jets, so they all use an air valve controlled by the computer to set idle RPMs
Ford calls their air valve an IAC(idle air control) Valve
Its on the upper intake by the throttle linkage, looks like a "can" on its side, has a 2 wire connector
Held on by 2 bolts, take it off
look inside and you will see the valve
Plug in its 2 wires if you took them off
Turn on the key
Valve should be open all the way now
Unplug the 2 wires while watching the valve, valve should move to closed position, it only moves 3/8" so not much but should move
Plug wires back in and watch it open again
Repeat as much as you need to decide it is working or is NOT working
You can only replace these with Motorcraft(Ford) brand, 3rd party cause other issues

Pictures of 4.0l IAC Valve seen here: https://www.explorerforum.com/forums...-w-pics.84220/
3.0l will be similar


If IAC Valve is working then you may have a bigger issue
2004 to 2006 Ford Ranger 3.0l engines had bad heads installed at the factory, the exhaust valve seats would get loose and recess into the head causing lower compression and misfires

Fords TSB seen here: https://www.therangerstation.com/for..._05-26-3.shtml

Because of your random misfire codes it fits this issue
And unfortunately it means you need new heads or to have yours rebuilt with new valve seats
Do a compression test to confirm lower compression is some of the cylinders
2004 3.0l should show about 165-170psi compression on each cylinder

 

Thank you for the input RonD,

I'll be checking into it.