Hi first of all just wanted to say thanks to everyone in this forum I have learned alot about problems associated with my truck.

I have a 2000 ranger 4x4 xlt 3.0L and it has been idling rough. Now my first thought was a bad IAC. I have just replaced that which helped the problem but didn't completely fix the rough idle. Wanted to know where to go next. The check engine light is not turning on so I have no codes with which to diagnose anything. Any help would be great

 

Welcome to FTE.

When replacing the IAC, did you pull the B- battery cable to wipe the computers KAM memory, then do the cold & warm idle strategy relearn routene????

Have you had the computer scanned for trouble codes, you could have "pending" codes stored that haven't happened enough times to turn the CEL on yet & if so, knowing the code Numbers may provide good trouble shooting clues.

If all thats comes to naught, it would be helpful to know where you are on All past & present due sheduled maintenance items & the manufacturer of the parts used.

If all that is ok, you need to find out if you have a fuel, spark, or compression problem.

SO, check the KOEO & KOER fuel pressure at the fuel rail schrader valve.

Check for spark on each plug wire, with an inductive type timing light.

If thats ok, do a "wet down" test of each plug wire & the coil pack, with a spray bottle of water to see if idle is affected, or any arcing & sparking can be seen at night with the wet down test.

If thats ok, hook up a vacuum gauge to an intake manafold vacuum line & see what the vacuum gauge may suggest is wrong with compression.

Between posting your maintenence info & the results of those tests, we should be able to narrow down, or find your problem.

 

will a simple code scanner work or do i have to take it to be scanned by a big diagnostic machine. Am changing out the plugs and wires at the moment with some motorcraft ones. Will reset the idle after this since i have the battery disconnected.
Just checking that i bought the right plugs for the 3.0L AGS-F32-M.
They are part SP432 on the motorcraft site. I only ask this because the plugs that I've pulled out are tagged AGSF 22FM.

 

A code scanner should show any "pending codes", if you did the scan Before you disconneted the B- battery cable, as that wipes the computers KAM memory, so now it won't have any codes, until the vehicle is driven some & the problem still exists or shows up while driving.

Is your 3.0L a flex fuel model????
That might affect the spark plug specification, but the Motorcraft site will show the correct plug number.

There is a cold & warm idle stategy routene, that a forum search will turn up, that might help avoid idle, or driveability problems after the battery disconnect & computer KAM wipe.

 

ouh! check crankcase vent hoses for cracks. may be vac. leak!

 

well i finally ended up taking it into the shop for my mechanic buddy to take a look at it. He was dumbfounded by the thing but did a fuel pressure test and saw that the pump was only putting out 15psi, the spec is for 60.
Replaced that part and just about everything was fixed...the IAC that I replaced ended up being faulty so I tried putting back on the old stock one after cleaning it with throttle body spray and it seems to work fine.

Thanks for all of your suggestions.

edit: oh and the scanner wasn't really working I took a look at the fuse box and saw that both the 16 and 17 slot were busted. Replaced those fuses and things are working. (Didn't know my wipers weren't working either.)

 

Good find, fix & feedback on your problem/s & thanks for closing out your thread.

Yup, diagnostic connector power for the OBD-2 scanner, or scantool is provided through the cigar lighter fuse, so if it's blown, they won't work!!!!