I have a 01 Ford Ranger 4x4 3.0..several months ago it started running kind of ragged and stalling out now and then. Took it to Auto Zone and they checked codes said needed new spark plugs and wires. Put new ones on and still had the same problem..suggested we change the coil which we did and it helped for exactly 30 days before it started again. The truck will start back up immediately after it stalls out but its so aggravating. We also cleaned the throttle body today and no change was noticed. Auto zone now said we could have a vacuum seal leak but we can't seem to find any. Does anyone have any suggestions of what the issue could be?

 

Welcome to the forum

Does the stalling out happen only when engine is cold?
Or only after warm up?
Or does engine temp not matter?

Just for future reference, write down the exact codes you get when reading the codes, "I think it was"...." is worse than no code.
So write them down.

Autozone guys, for the most part, have no idea of what trouble codes actually mean, while they seem to be written in english they are NOT
Lean does not mean engine is running Lean
Rich does not mean engine is running Rich
Misfire does not mean spark plug problem
O2 sensor not switching does not mean O2 problem
ect......................
"Well what good are they?????"
They tell you what the computer is seeing, not what the problem is

So if you have any codes now post them

Vacuum leak is very easy to test for
On the upper intake by the throttle plate is the IAC(idle air control) Valve, looks like a can on its side
It will have a 2 wire connector, you need to know where this is for the test

After engine is warmed up and idling, should be 700-800 RPM
Unplug the 2 wire connector on IAC Valve
Engine RPMs should drop down to 500 or so, engine may even stall, either is good, no vacuum leaks.
If idle doesn't drop then you have a leak.

Put your old coil pack on and see if problem clears up again.

There is no reason new coil pack should work for 30 days then have same problem return.
So either it is a "similar problem", NOT the same problem, or 3rd party coil pack has failed, should still be under warranty, take it back.

 

Ron D....we did exactly as you said..the rpms dropped to 500 but it did not stall out. So no vacuum leak.

 

Also it doesn't matter if the engine is cold or warmed up..it just stalls out.