Hey folks...
just did a valve cover gasket replacement on my 1999 ranger 3.0 4x4...not sure what i did but now she is running very rough at idle and wants to die after few minutes but doesnt give any codes on my scanner...uggg...prob messed up some sensor...any ideas? Help and thanks!

 

Probably forgot to plug a vacuum line in, that would make it run like crap and there wouldn't be any codes.

Check the PCV check valve passengers side valve cover and make sure it's connected to the vacuum port underneath the upper intake manifold.
That's a common area of trouble because it's hard to get too and easily missed.

There's another big vacuum port on the upper intake manifold for the EVAP system too.
It's nearer the front , same side, below the EGR diaphragm, down low _ kind of out if site.
The line follows to the EVAP purge solenoid on the fender well.
It's also a common mistake to forget to hook that one up again.
It would run like **** with out this hooked up _ majour vacuum leak with that line off.
This one however would throw up a code, but not right away, the computer takes it's time giving EVAP codes.

There's also the vacuum port at the back of the upper intake manifold that needs to be checked (this is the last vacuum port), but then all you dash climate controls wouldn't work, amongst other things under the hood, like your DPFE sensor circuit.

And you didn't mess up a sensor, you may have forgotten to plug one back in, but sensors don't up and suddenly fail. They're usually the last thing to go, if ever.
You would have had the air tube removed to do the job, so the MAF sensor maybe, but that's a pretty obvious one to miss, and it would throw a code.
Same with all the sensors on the throttle plate...
Make sure they are plugged in properly and you didn't get them mixed up, it is possible.

 

Ok thanks a bunch Jeff R1.... The vac port on back of intake manifold wasnt connected runs significantly better now and stopped wanting to die...still very rough however and after short test drive gave me a code P1151...investigating that now ...thanks again my friend��

 

Check your firing order as well. Pretty easy to get them wires crossed.

 

Yep u nailed it figured it out earlier today had 2 plug wires flip-flopped ...amazing since i carefully marked them with a Sharpy...DOPE...thanks everybody runs like a charm now😎