When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
99 Ranger 3.0, 203K, 5-speed. Over the last few days the idle has got steadily worse. It bounces, sometimes a minor amount (50-100rpms), other times more (drops to 300 then back to 1K). I have no CEL, tried disconnecting the Idle Air Control Valve and setting the curb idle higher, same bouncing, but only 50-100rpms. I cleaned the IACV as well, but it wasn't too dirty. I checked the EGR, looks very clean inside. I cannot feel the surging under load, only at idle (feel it in neutral at higher rpm's as well). Only other thing is it seems to ping quite easily.
Yah I finally opted for an updated fuel pressure gauge about 3 years ago for my vehicles when one was randomly stalling. I opted for the inexpensive $19 Harbor Freight model, but used PTFE ribbon dope on the gauge & line connections to make sure they didn't weep. It didn't have the pressure bleed off valve, which is handy to have when we also want to perform a volume over time test, or to relieve pressure without spillage before disconnecting the hoses, but it served its purpose for the one time I've used it.
Is the ping when the engine is under load???? If so have a look for vacuum leaks & at the spark plugs for a deposit load read, make sure they're the correct heat range, properly gapped & torqued in to spec.
I purchased the truck a little over a year ago w/ 180K. It's knocked since purchase. After purchase I installed new plugs (cannot remember what they were now, from NAPA), PCV, air filter, changed coolant, and removed radiator for flushing. Truck runs a consistent temp, see's a steady diet of Chevron, and gets around 21mpg. It uses hardly any oil between 5K changes (Ford oil n filter).
Only recently has the idle problem crept up, and it seems as though the knocking has gotten worse. It is only under load, but not what I consider a heavy load. I was unable to run in 5th gear @ 55mph towing my 2-place sled trailer with a small amount of scrap iron (1,000lbs.) w/o knocking. This was on flat ground. It's a Flexfuel truck, which seem prone to detonation from what I've read.
Since its a flex fuel 3.0L it has special heat range spark plugs specified & since its a waste spark ignition system, that works the plugs Twice as hard (fires them Every rotation of the crank shaft) to fire on the power stroke, then again on the exhaust stroke (waste spark), we need at the minimum double platinum, better yet the newer specified fine wire iridium enhanced center electrode, with platinum pad side wire design, that'll maintain its spark gap longer in our waste spark ignition system. So, the Motorcraft plugs & wires are recommended, as they're of good quality & designed to take the double work load.
If you fill up with mid, or premium octane fuel, does the ping stop????
First, many thanks for taking the time to help out !!! Second, are those super wazzu plugs your referring to what the Ford dealer carries ? Third, I really first noticed the detonation when the A/C was on going up small inclines. I then tried super, and that did indeed quiet it down quite a bit. BUUUT, I have a decent grasp of octane, a mid comp, al head engine shouldn't require supreme.
The Dealer probably carries the fine wire design plugs, so do most parts stores & site sponsors. I'm using them in my Fords & one Chrysler with waste spark ignition, all with positive results of quicker year round starts & the spark gap staying in spec Way longer. As the spark gap is always wanting to open up, gap the fine wire plugs at the minimum spec gap, using a Wire gauge. Sneak up on the gap slowly, so as not to damage the platinum pad, or fine wire center electrode by pulling the gauge through too tight a gap.
The reason I ask about if increased octane helped the ping, was to try & get a clue to what may be causing the ping. Since the result was positive, too hot a plug, or combustion chamber deposits may be at fault. Since you say you've been using Top Tier Chevron fuel, the ping happens under light load, that sorta leaves the plugs heat range question up on the suspect list right now.
The air filter you replaced wasn't one of the oiled foam, or cotton gauze types was it????
Standard filter element. I'm going to run some Seafoam through the engine. With 203K I on it, deposits are a high probability. Do you have the Motorcraft plug number ?