I have a 1998 4.6 with 87 k on it and as far as maintenance i have done everything except for changing the plugs and wires. the truck runs really smooth no problems at all,so should i just keep driving it till something goes wrong or stay ahead and change plugs and wires?is there anybody outthere that's gone 100k with out changing plugs and wires?

 

It can be done, but at 87K, the plug gap has widened and it may get a bit better mileage if it were tuned up now.

 

i tuned mine up at 50k, and hopefully it lasts a really long time i guess from what everyone says, it shouldnt be done TOO often, but i look at it like this, an oil change is supposed to be done every 3k miles for heavy duty (by the owner manual anyways) i would suggest a frequency of about 2500 miles or less... why wait? does it not mean that much to you? lol do the tune up, make sure you use good quality parts the FIRST time (dont make my mistake, took 2 shots to get the right set of plugs/wires on it) and dont worry about it again until you get a misfire...

 

I didn't change mine until 105K miles. Had a miss but it was a coil pack. Just changed entire secondary ignition while I was in there.

 

My biggest fear is if you wait to change the plugs at around the 100,000 mile mark it can become "difficult" to remove the factory installed plugs. Especially since they don't use anti-seize on the threads. And with our aluminum heads the plug threads are more prone to damage for "difficult" removals. I want to keep my 2002 truck for a long time( I'm a cheap bast*rd ) so I'm going to change my plugs in the 50-60,000 mile range and use anti-seize on the threads. That way my second set of plugs can go longer without fear of damaging the head threads on removal. Plus after 50,000 miles the platinum pucks on the electrodes do wear down and the gap does increase and the plugs start wearing even faster. Your gas mileage and performance does decrease. Even if you don't notice it for a while because it's gradual, but the performance and mpg are degrading.

Whimsey

 

I bought my 98 last spring w/104,000. Not long after I changed the plugs only; went with NGK V-Power. I've always had good performance from them, but they were toast after 20,000 or so. I now have new wires, coil packs & ASGF 32FM plugs. This setup only has 5000 plus miles, but I'm fighting a pinging problem; not sure where to look. Think I'll let a mechanic friend of mine take a look at it.

 

Dough, the plugs are probably not part of your pinging problem. The only relationship I can see is a plug from a hotter heat range could promote pinging. Not very likely. Much more likely are plugged EGR ports or other EGR problems or carbon buildup in the combustion chamber. Lean conditions and spark timing issues are not nearly as common they used to be. Also, if you're hearing it, the knock sensor wasn't or the strategy to reduce it was unsuccessful.

I occasionally get light pinging at mid to high throttle. I find a long interstate hill (rare here but I go to Pgh often), downshift and accelerate hard in 3rd from 3500 to 4500 RPM, let off and do it again. It always clears up the pinging I've got. My problem is I live 1.5 miles from work and only drive out on the highway once or twice a week or so. Plus I drive like Grandma. If I don't really get after from time to time, I get carbon. Fortunately it doesn't take chemicals or frequent hard runs to clean it out.

 

Try cleaning the MAF.

 

I cleaned the MAF & TB; still get the pinging. Also, and this may be totally unrelated, I get a "shudder" on occasion when the trans shifts into overdrive. It reminds me of the sound & feeling you get when you drive on the edge of the interstate on the rumble strips. And sometimes it shudders at low speeds under load. Trans trouble? I've changed the fluid & filter in the last 25k. And checked the u-joints & driveshaft, although it has been a while.

 

Did you power flush the tranny or just drain the few quarts in the pan?

 

The Torque converter has a drain plug in it (according to the transmission shop)
Changing this fluid helped my transmission shifting
the shuddering went a way after a tank of gas

 

No, I just changed the filter & fluid in the pan. Guess I'll give that a try.

 

I experienced the exact same symptoms on my V-10. Even turned around and went back to take a look at the road suface to see if that was the cause. I couldn't tell if it was a tranny problem or an engine problem until I hooked up the scanner, which revealed that one of the COPs was misfiring just as it was going into overdrive at around 35 mph. Not enough to set a code, but enough to register significant data accumulation in the Mode 6 misfire counter. Replacing the COP fixed it.

 

Well, mine doesn't have the cop's, just two coil packs. I'm planning on tending to the trans tomorrow, new fluid, filter & flushing.

Oh, new EGR this weekend & STILL pinging!!! O2 sensors next? Also, any chance the MSD DIS 4 could help? I've always had good luck w/MSD stuff; that's the kind of wires & coils I have on it now with less than 10k miles on them. Thanks.

 

Dough,

By new EGR does that mean you've replaced the DPFE or EVR or EGR valve? What I meant by the EGR is that passages are probably plugged up. You can test for blocked EGR lines by pulling the vacuum line off of the EGR valve (looks like a little flying saucer) and pulling a vacuum on it (mightyvac) while idling. If the engine stumbles and perhaps stalls, then the EGR is flowing when the valve is open. If no change in idle, the EGR is blocked.

If you don't have a MightyVac or equivalent to pull the EGR valve open, you can use the vacuum line from the EVR. Trace the vacuum line from the EGR valve, it will end at the EVR which has two vacuum lines. Disconnect the other vacuum line from the EVR and hook it to the EGR valve. That should pull it right open.

I suspect that the most common reason to ping is carbon buildup in the cylinders and on the valvestems. Run some Techron through it but also run it hard for 10-15 seconds at a time. By hard I mean wide open up to 3500-4000 RPM. Do that 5 times after it is thoroughly warmed up, especially after running Techron through it. That may help your pinging more than anything.

It is very unlikely to be the O2 sensors. They usually fail by slow response until they don't respond any more. Having an O2 sensor shift and command too rich or too lean is very rare.

Let us know.