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Old 07-26-2011, 11:08 PM
hoerth hoerth is offline
Liking the Ford Ranger Forum
Join Date: Jul 2011
Posts: 17
Default another rough idling scenario -- '99 3.0L

Truck started rough idling last week and I've reviewed lots of forum threads for solutions. But still is rough and really gets bad at 40 mph and 1500 RPMs. Lousy power going uphill, I started by adding fuel stabilizer and Lucas injector cleaner to the fuel tank. Depleted the gas and added more injector cleaner with next fill up. Changed plugs and wires. Put in platinum Autolite plugs. Cleaned MAF sensor. Replaced the $50 DPFE sensor (Delta Pressure Feedback Valve). No visible loose or worn hoses. So what do I try next? Clean Idle Air Controller (IAC)? Can I use the MAF Sensor cleaner on that since I bought a whole can but only needed to use a little? Or carb cleaner? Does changing fuel filter make a difference? Throttle body cleaning may help from what I see in other posts. What about EGR valve. Clean or replace? Seafoam a last resort?

Additional notes some of which may be related: I ran the gas tank down real low just prior to this happening. Using O'Reilly's scanner CAN )BD2, I get codes PO305 (cylinder 5 misfire) and PO174 (system too lean bank 2). 160,000 miles on the truck. Serpentine belt's been squeaking but I remedied that by cleaning grit off the center pulley using sandpaper. Front passenger side floor's been getting wet which sounds like a heater core issue.
1999 Ranger, 3.0L, 6 cylinder, automatic, 4x4, XLT Cab
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