Changed Spark Plugs

dodge123 · July 18, 2011

I decided to change plugs and wires this weekend. I had a bit of a rough idle for the past six months since I bought the truck. I replaced the AC Delco iridium plugs and wires which were probably the originals with double plantinum plugs and Napa Belden Max wires. All the iridium's looked exactly the same so I know the engine is healthy, even at 230K. The wires were a great fit and a bit tighter than the Delcos. The truck definitly idles smoother now and should improve gas mileage a bit. I also ran seafoam through the gas tank a couple weeks ago and it seems like I have gained a bit of fuel milage from that.

Dozbubba · July 18, 2011

Clean the throttle bore also if you haven't already. My dad was having idle problems so he cleaned it and cleared it rite up.

dodge123 · July 18, 2011

Oops forgot about that. Ill do that tomorrow night. Id like to know how much buildup is in there.

Kodiak450 · July 20, 2011

230 k, how does the engine and tranny feel to you? I remember the GM salesmen telling me when I bought my 03 2500HD how the engines GM uses are rated for 200k at least which is a far further cry from a Ford truck engine where once you reach 130,000 miles the engine starts to fell tired. I only have 77k on my 2003 silverado 2500HD, so to me my truck still feels like a new truck.

Did you put all that mileage on or buy the truck used?

redjewel2ss · July 20, 2011

nice job!

i'm surprised the double platinum plugs didn't cause any issues. i changed the stock iridiums in my dad's '04 silverado @ 100k miles to those e3 plugs and it ran like crap. after exchanging them for a set of new ac delco iridium's it ran smooth again. i've heard from other people that these engines only run well on the plugs they were designed for; iridiums.

Kodiak450 · July 20, 2011

I tried those e-3 plugs and they ran like crap in my truck too. I winded up buying the same OEM plugs and the engine ran much better.

bmp5484 · July 20, 2011

I almost bought the E-3 plugs also, but luckily I heeded the advice of the man at the parts counter for once and got the iridiums. It ran like new and I've seen quite a few people who say nothing works like the oem Delco. They better work for $7 or $8 a piece or something lke that.

dodge123 · July 22, 2011

I bought it used. I'm second owner. When I got it it already had 213K. The transmission was replaced just before I bought it with a reman one. I recently changed the filter and fluid. The engine runs decent. It has only what I can describe as maybe piston slap when idling. It also doesn't have the acceleration/power that I think it should if new. The bearings are probably worn down pretty good. It doesnt burn much oil though, less than a quart per 3000 miles between oil changes. I am a little worried that doing much heavy towing is going to blow the motor quickly at this point in its life.

I checked the throttle body bore and there is a bunch of black soot behind the throttle plate. What should I use to safely clean it out? I dont want to get chemicals or anything that may damage the intake or engine in there.

I should post a picture of the iridiums so everyone can see the condition and give me an opinion. There is some white buildup on them but I read that can be attributed to using a fuel additive like sea-foam which I recently did. Before I bought this I had no experience with those plugs and to be honest when I first took one out I thought "well there's your problem" due to the pointy electrode.

redjewel2ss · July 22, 2011

either removing the throttle body completely and cleaning it with some carb/throttle body cleaner, or using the seafoam spray to cleanup the inside of the intake manifold will do the trick!

sack1 · July 25, 2011

nice job!

i'm surprised the double platinum plugs didn't cause any issues. i changed the stock iridiums in my dad's '04 silverado @ 100k miles to those e3 plugs and it ran like crap. after exchanging them for a set of new ac delco iridium's it ran smooth again. i've heard from other people that these engines only run well on the plugs they were designed for; iridiums.

There's no reason an engine delivered with iridium plugs must continue using them and certainly not a specific brand. That metal is there for longevity, thus the 100k change requirement. I replaced my OE iridiums (Denso) with Bosch Platinum and all is well. I have the 8.1 liter.