1999 3.0 Engine tick at warm idle / knocking under load

[I support common sense]

Howdy, my name’s Daniel. I’ve got a 1999 Ford Ranger with a 3.0l flex fuel engine 4 speed automatic 2wd XLT. 302,500 miles on it. I’ve had some misfire trouble out of it for a while since I’ve had it (1 year). And more recently (3 or 4 months) it’s been pinging when it lugs down in overdrive or above 3,000 RPM pulling a load.

I’ve done all the common things to it. I’ve replaced coil, plug wires, plugs, all within the last few months. I’ve removed and inspected the injectors although I did not replace all the seals. I’ve removed and resealed the upper intake and cleaned it and the EGR. I’ve run plenty of injector cleaner, and I’ve cleaned the throttle body. The fuel filter and air filter have been changed.

The reason I’ve come back to the forum is my engine has just started ticking at idle after it’s warmed up. I just noticed this yesterday and again this morning when I pulled in at work. I’m thinking it’s a collapsed lifter, and maybe this has caused my misfire that only shows up when it’s warm. The engine has always ticked just a little across multiple cylinders, but this is a solid steady tick, I think it’s coming from one cylinder I’ll have to check it with my stethoscope. Oil was changed 2500 miles ago Mobil 1 5W-30 Full Synthetic Motorcraft filter. When it was ticking the oil pressure was between 15 and 20 psi according to my Bosch analog trio guage set, but I’ve seen it as low as 13 psi before. Dipstick was sitting just over halfway between center. I’m considering pulling valve covers as my next step, and rechecking plugs and compression.

I would really appreciate any input or helpful advice. I’m not completely new to “mechanicking,” so don’t be afraid to get technical.

Edit: I’ve also replaced both upstream o2 sensors and cleaned the MAF sensor. No codes currently, but I have had cylinder misfires show up and disappear in the ECM.

 

[RobWigglezz]

How many miles are on it? If it's over 150k, have you ever replaced the cam sync? They can wear out and bypass oil pressure.

And when you say knocking, are you sure it's not detonation or pinging under a load?

 

[I support common sense]

Thank you for the response.
It’s got 302,500 miles on it. And I doubt the cam synchronizer has ever been replaced. I’ll definitely look at getting that changed.

Yes, I meant pinging. It’s pre igniting under load, either in overdrive when climbing a very slight incline unloaded around 1600 RPM 45mph; or when loaded down with a trailer climbing at 3,000 + RPM.

When I started it after work it had been sitting for a little over ten hours, but in the hot sun. It was ticking when I started but not quite as badly as when it was warmed up.

 

[RobWigglezz]

300k! Yea I would attribute the low oil pressure to the cam sync. That's possibly causing the lifters to take their time pumping up.

As far as the pinging, try using 93 octane next fill up. Here's a tsb about it.

Ignition Coil/PCM - Spark Knock On Acceleration — 2000 Ford Ranger 2WD V6-3.0L VIN V Flex Fuel Service Manual | Operation CHARM

Detailed repair manual for the 2000 Ford Ranger 2WD V6-3.0L VIN V Flex Fuel.

charm.li

 

[I support common sense]

I should have included that too. I filled up with 93 octane twice a couple weeks ago and I didn’t get a single ping. I also gained a lot more torque which I suppose is to be expected.

I replaced the coil pack a few months ago, and it also started pinging a few months ago, although I couldn’t tell you if they had any relation, I don’t doubt the possibility though. I wonder if I got the wrong one. I still have my old one somewhere so I’ll take a look at it and see if there’s a difference.

I don’t understand why I would need to replace the ECM though.

 

[lil_Blue_Ford]

I should have included that too. I filled up with 93 octane twice a couple weeks ago and I didn’t get a single ping. I also gained a lot more torque which I suppose is to be expected.

I replaced the coil pack a few months ago, and it also started pinging a few months ago, although I couldn’t tell you if they had any relation, I don’t doubt the possibility though. I wonder if I got the wrong one. I still have my old one somewhere so I’ll take a look at it and see if there’s a difference.

I don’t understand why I would need to replace the ECM though.

ECM should be investigated for burst capacitors and internal damage. Unfortunately it’s something that continues to be an issue as time moves on

 

[I support common sense]

ECM should be investigated for burst capacitors and internal damage. Unfortunately it’s something that continues to be an issue as time moves on

so are you saying the symptoms I’m saying justify pulling the ecm out? It just seems like it would be something more simple than that. In my head I can’t see a bad capacitor causing a misfire.

 

[SenorNoob]

Since 99 should have the ignition module built in to the PCM it's a possibility. And dead/dying capacitors have been know to go out after warming up in other circuits. Like the sound output on a flatscreen I have. 2 dead caps and no sound. It worked for a few minutes then quit. If a capacitor is acting as a buffer on a circuit, who know what it could do when it dies.

That said their are most definitely other possibilities. Since you say you have a stethoscope, use it. That'll help you narrow things down faster. Wouldn't a soft lifter also show up on a vacuum gauge?