1998 windstar running rough, replaced plugs and wires, no change. acts like a vacuum leak, but cant find anything. auto store said it could be the egr pressure control. runs fine sometimes then just starts running really rough, even dies when idling. when I changed plugs one was a little wet. help

An auto parts store does not give out advise

They are parts counter sales people-- not mechanics

Spark plugs seldom fail in your lifetime, so you need to
check for vacuum leaks at O2 Sensors,Exhaust leaks,Vacuum leaks
in inlet ducting ,pcv vacuum leaks,egr system issues

Check & listen to hear if injector all click & have same resistance

An OBD Codes for a cylinder doesn't have to be correct

You have mechanical integrity also

You don't have the tools to test as needed I don't suspect
or you could check cyl contribution,fuel trim,fuel press,cyl misfire
counts,O2 switching times,etc

This truck has problems with the cover inside intake leaking vacuum and causing rough idle and oil usage , its hard to say what your problem is with out testing, have you had the check engine light scanned for codes? what year is this dodge?these also had intake leak problems. try starting the engine and let it idle and then with some carburator cleaner spray around intake gasket and see if idle changes if it does then you have a intake gasket leak, another problem may be a leaking injector, try some sea foam in the gas tank and run a half tank of gas and see if that helps, otherwise a fuel injection system cleaning would be the way to go but this is only if its an injector problem, if this truck is 1996 or newwer have the computer scanned at an auto parts store for any codes. if there are codes let me know what they are even list the code and #. good day

If you have a manifold leak that will cause a MASSIVE vacuum leak and make it run rough at idle only. Look at your short term fuel trims with a scanner, if they are way negative you have a vacuum leak. Fix the intake manifold leak and that will fix your problem.

Try changing the coil pack

Pretty hard to diagnose without a scan tool to check the fuel trims. rough guess is either a vacuum leak or bad coolant temp sensor. But I sure wouldn't replace either of those without seeing the results from the scan tool

it's not likely a bad o2 sensor would cause it to run rough, but the catylitic converter, which is what the o2 sensor reads the flow of, would cause the car to idle and run rough.If you take it to an auto parts store to have a diagnostic test ran on it( most major parts stores will do this for free), thecodes it gets would help pin point it alot better.

If the engine seems to run fine over 1450 RPM maybe there is a vacuum hose leaking or EGR valve is slightly stuck open. Any help from the OBD II trouble codes? Or is there simply no MIL and no stored information in the OBD II computer read at the local parts store through the connector by the drivers knee?

my van was doing the same thing and went to auto zone and they told me the same thing but i did nothing and it stopped on its own

I have the same problem!Running on three.I have checked compression,wires,plugs.Changed injecters,plugs.
3 mech.cant figuire it out???

While it could be a vacuum leak due to a cracked hose, it may also be caused by a failing electrical connector. Phantom problems can occur when a vehicle is used in some climates and cured simply by dis- then reconnecting plugged items.
The fuse problem may be caused by a failing ABS controller; these devices handle fairly high currents to modulate braking action so one of he drivers (solid-state) may be trying to die. Probably the only way to 'trap' this one is by replacing the ABS controller and they are not cheap. I don't know if the ABS system communicates with the main ECU but there may be a stored error code in the ECU memory indicating the nature of the failure and most of the chain auto parts stores will scan your ECU free of charge; call them to confirm.