Why has it lost power?

I drive a 2002 Silverado regular cab with the 4.3L. I keep it maintained... change the oil every 3k miles (even switched to Mobil 1 Syn). I put a fresh air filter in about as often as I change the oil. Also changed the fuel filter recently. Run injector cleaner often. Today I ran some Sea Foam through using the brake booster vacuum method. I did notice a little power increase after that but not what I expected. It feels like the truck has lost ~20 RWHP since I got it with 19K on it, now has 37K. The next thing I can think of is to change the plugs. I have a feeling it won't change anything though. What would you look for after that?

i would just regap the plugs. little to soon to change them..JJ

Thanks for the quick reply JJ. I guess the reason for that would be that buildup on the plugs could change the gap? Might just need a cleaning. Any more ideas anyone?

gap would change as metal disapated from electric discharge will be slight but can make a small difference. My truck seem to have lost a, little step here lately and i havent checked my plugs either but i would guess thats part of the prob at 60,000 plus miles. Everything else your doing sounds appropriate . I do run a double dose of injectore cleaner with a tank of 93 octain gas about every three or four months and that seems to perk it up.. jj

Someone else has got to have some more ideas?

Buy a new engine like me lol. Just kidding, I'd check the air filter and the fuel filter again. I once had to change mine 3 times to get some crap from a bad tank out of it.

throw in a 4.8 :D

Sheeeit, I had a blown 5.3 I woulda given you lol.

You might try some Red Line Complete Fuel System Cleaner.......... seemed to work for me as it really perked my Silvy up!! One bottle treats 100 gallons but you use a whole bottle first time and then an ounce or so each tank full after that......... although I haven't been doing that way.
I just use an entire bottle every 10-12 tank fulls. Guess I'm gettin' lazy in my old age.

Please let us know how the STS works out. I posted an inquiry about it two months ago and got no responses.

I probably won't get it installed until next year...it's not exactly smog legal here in CA yet, so I have to wait until after December to install it, which is when I gotta smog.

So pretty much December 1st my day will go something like this:
8am - Smog check......9am - Install turbo :evillol:

Wanna read onthe STS, go to www.LS1TRUCK.com (http://www.LS1TRUCK.com) THe dude who's tuning my truck installed one on his 94 and has raved about it.

jeverett,

keep us posted on that nelson tune. i was readin up on it and it sounds pretty tempting. I kinda need a new PCM anyway cuz the one I got now is out of a suburban :iceslolan

Allen called me yesterday, but I was still tweaking another system I put in a Duramax, soo..I didn't get to talk to him. I'm about to explode waiting on it.