Have a 94 1500 4wd with a 2000 318 motor in it has ran fine for years now it will start good and run good tell you drive it down the road then will start to miss and idle really ruff like it has a big cam in it i have so far tried a new fuel pump new cap and rotor new intake gasket checked all vacuum lines new pvc valve new filter new throttle position sensor any ideas what could be causing this

 

When you changed the intake gasket, did you also do the plenum gasket?

How many miles since the tune up?

Possible cam, or crank sensor as well......

 

I found with the 5.2 in the dakota was the idle soliniod on the throttle body, can cause it to stall if it doesn't open but can also run rough if only opening partially.

 

any check engine light? Have you look at the plugs?

 

yes i replaced the plenum gasket would bad plugs or wires couse it to run good at first then start to misfire and idle bad 5 or 10min after driving it

 

its a 94 so its the older style check engine plug an i have been having a hard time finding a scanner to hook up to it

 

Most auto parts stores (round here anyway) will have an obdI scanner you can use for free. You may have to ask them for the obdI dongle, but it shouldnt be hard to find.

So, does it idle fine when you start it, then give you problems while driving, or is it missing all the time?

If its missing under all conditions, your plugs and wires could well be to blame (as a rule, generally when you do cap and rotor you do plugs/wires at the same time). Also, you may have disturbed the cam position sensor (or distributor placement, i.e. rotated the shaft a bit) when you did the cap/rotor.

 

I would be leaning more toward a failing O2 sensor, than anything else...... Yours shows the signs.

 

its random sometime it starts up and runs smooth and will drive smooth for a few then it will start missing then idle ruff

 

https://dodgeforum.com/forum/1st-gen-dakota-tech/182034-obd-1-codes.html