P38 lacking power?

[superpowerdave]

My wife has a 2000 P38 with 75K on the clock. Truck runs great, just not pushing as much power as he used too. I know, these trucks aren't built for speed, but he just doesn't feel like the acceleration is there anymore.

We've swapped stock plugs for Bosch Plat +4s, got a set of Magnecor plug wires on order, have done the Seafoam treatment through the intake manifold (smoked like the Marlboro man but no significant gains, unlike my DII), used Lucas fuel additive ... just not sure where else to go from here.

Truck gets regular maintenance, is well taken care of.

Any ideas?

[eclayson]

Just a couple of options which might help
1) Check air intake for leaks
2) Check ECT sensor
3) Mass air flow sensor (common failure on p38)

Is the ecm in limp home mode?
Try getting a code reader on the car.

Hope this helps

[Disco Mike]

You need to get the Magnacor's on there prior to doing anything else, need that extra voltage to fire up those plugs.
Once you have that done, try a bottle of SeaFoam thru your gas, now with the better spark, you should see some improvements.
I a guessing you have no Codes?
Mike

[superpowerdave]

Right Mike, no codes. Awaiting plug wires currently. Hopefully this week sometime. Just had the P38 in for service (alignment done) and they scanned him just in case but no joy.

I wish I could describe it better, but he just doesn't feel right, like he's lost a step or two. Maybe I'll have some answers when I drop the new plug wires in. Oh, on that note, anybody done a plug wire replacement on a P38? The Disco II was cake for me (small hands I guess) but there seems to be even less room than on the DII. And since I refuse to remove the intake manifold (matter of strict principle I suppose) this should be sporty.

And yes, if I ever meet the guy that designed the spark plug placement on the P38 I'll probably punch him in the face. If you've done your own plugs you know where I'm coming from!

[Freeloder]

You might want to check the throttle cable on the engine. I have seen the adjustment screw/nut come loose on several P38s. Turn the engine on and adjust the screw/nut on the main throttle cable (not the one for the CC). It should be tight and stop just before the engine RPMs start to rise. Worth a shot.

[02RhinoRange]

I'm sure you're trying to avoid a Dealership visit at all costs, but I recently had my plugs and wires done, and my LR tech reset my "adaptive settings".
It basically resets all of your shift/rev points.
He told me for like the first 100-200 miles, when pulling out of an intersection, or merging onto the interstate, he told me to "get on it!, hard." After doing this for about a tank of gas my Rangie now has more power than when I bought it, not to mention runs smoother too with the Magnacores...