my 1999 Ranger 4X4 with a 4.0L is really running rough when in gear at a stop,it also has started sputtering when I cruise at a contstant speed especially bad at about 35 MPH and at 55MPH when cruising at 67 runs smooth. I had a CEL come on showing running lean, I replaced both upper and lower intake gaskets aand the cel cleared, cleaned the maf and IAC but still sputters and runs rough, any ideas on a fix?

 

How are your spark plugs looking

 

Welcome to FTE.

You may have more than one problem.

Post All of the trouble code Numbers you had before the repairs, along with which tranny it has.

After the repairs & cleaning, did you clear the trouble code/s with a code reader, or scan tool, or by disconnecting the battery B- cable, to wipe the corrupt KAM fuel trim tables from the vacuum leak, or dirty MAF sensor, or acting out IAC, so the computer knows that repairs have been made & it's supposed to begin building new fuel trim tables right away????

If you cleared the codes, did you at least go through the cold & warm idle relearn routine, or properly do the lengthly Ford reinitialization drive routine???? If not, both are posted on the forum & a search will turn them up.

Did you use a non residual cleaning product like CRC or Valvolene MAF spray cleaner to tidy up the MAF sensor, didn't poke or damage or contaminate it's sensor & kept it squeeky clean on reinstallation????

Cleaning the IAC may not work, or last, it didn't for me, but was a good trouble shooting step & I knew what to replace when my hanging up high idle problem reappeared after the cleaning.

^+1 on the spark plugs & I'd add wires too. In fact where are you on All due past & present scheduled maintenance items, like filters, PCV valve, ect????

More thoughts for pondering, let us know how it goes.

 

Wow cant beilive it, I had pulled one of the plugs when I had the upper intake off and it looked fairly new but I did not pull any more. I remember when I bought the truck a year ago the guy said he had just pulled them. Well tonight I pulled them all, amazingly there were two that were original to the truck. I bought six new gapped them to .54 and it runs like a dream best it has ran since I bought it. Something so simple. Thanks for the great advice.

 

hahahah AWSOME glade it was a simple fix, I was pretty sure that was it because iv seen that happen once befor and the guy was all worried it was the distributor and i said well check out the plugs first, and walla

 

Glad to hear new spark plugs seem to have put the fix on things. Hope you opted for the new specified iridium finewire center electrode with platinum pad side wire plug, for our "waste spark" ignition system, as it works our plugs & wires Twice as hard as a single coil ignition system, so the new fine wire iridium plugs will last a lot longer than a copper core, single platinum, or double platinum plug in the waste spark ignition system.