2000 SOHC Motor - Pinging

[ebexp2000]

Ok, I've done my homework already, but I'm still stumped here. It's a 2000 Explorer, 4.0 SOHC motor. No mods. 4.10 rear end. 5 Speed auto trans.

The engine has been pinging for some time now. It's a loud groaning noise, while in overdrive, especially when pulling the boat (approx 2000 lbs max). Even on the almost flat surfaces, pressing the gas pedal just a tad results in a loud groan (which I'm told is a ping). It then makes absolutely no power, and does not accelerate unless the transmisson shifts for more power. It also will ping without the trailer, but less.

The engine now has 66,000 miles. The lower-intake manifold gaskets were replaced at 50,000 miles, along with the chain tensioners. Also had the primary chain tensioner replaced. Have run sea-foam through the brake booster line several times, and although it helped slightly the first time, it's still pinging a lot. Premium gas helps, but not much.

Bottom line is that instead of making power under load, the engine groans loudly, which I'm told is pinging.

What should I do next?

 

[BradE.]

At 66K miles, check condition of plugs and wires. Replace if needed.

Clean MAF sensor.

 

[X24]

The SOHC should not ping. It has sensors that will retard the timing if that happens. Sounds like the groan you're getting is from it being in OD and not shifting out. Next time try lifting your foot off the pedal and putting it back on before you try to get more power out of it. When I do that the torque converter will unlock. Some people say when you're towing you should leave OD off, even on the highway. I'm sure you know how much different your truck drives with 4 people in it... Imagine putting 13 or 14 people in there. 2000lbs is quite a bit.