Is there really any reason to change spark plugs if the motor is running fine and your gas mileage hasn't changed since you bought the car? I've got 6 plugs in the back of my truck that I bought last year but I've been waiting until the car tells me it needs them.

 

depends on quality of plugs, have you checked them to see if they look "good" and burning clean.

i check mine every 25,000 miles and anti-seize the threads.

i think some plugs are rated for 100,000 miles. i know if i buy a car i always change plugs and wires as a welcome to the family routine i do, in addition to fluids and other general maintenance things.

 

I assume the original plugs are the best quality? They have never seen the light of day since I bought the truck in 2000. I thought about doing them once but had trouble even getting the boot off the one plug I tried. In theory if you don't have problems with running lean or rich and your rings aren't blowing oil the plugs should last a long time. If I'm going to pull the plugs to see if they look OK I might as well put the new ones in.

 

If the truck is running fine don't change them if you pull them just to check them you might as well put new ones in as a few are a pain in the *** to change. I would check the cap and rotor before checking plugs,and if you do change plugs do the cap and rotor at same time.

 

I pulled mine last year when i bought my Jimmy in Feb. I wanted to check the compression to make sure all was well. Compression was good but the cathodes on all the plugs were fairly well worn. The truck was running OK at that time but with a new set and a new EGR it ran great.

 

Once I had a car that was running OK but I decided to put new plugs in. The plugs were rusted into the block and I managed to break off the ceramics so I was left with 7 cylinders. I finally had to drill out the old plug then chase the threads. I don't know what I would have done had I screwed up the threads in the block...I don't know if you can use inserts on a plug...never heard of anyone doing it at least. I'll spray some penetrating oil on them a week or so before I decide to change the plugs.

 

helicoil

and i've always been told when you break it loose. loosen it alittle then start tightening it then loosening it. that is what i've heard before.

 

First of all: the Plugs will tell the condition of the upper valvetrain & mixture issues: this is for certain! Any loss in performance or fuel economy? Look at the plugs! The #3 is not hard at all-just look at it! Pull the left front wheel! Same is needed for simple access for the right side as well! my advice for any late model motor:use never-sieve! Every time!
Same on the lug nuts!

 

i was in fleet management for a while and had a boss that was a real tightwad. so basically plugs didnt get changed and they would burn off around 100,000. usually just get a misfire and when you pull the plugs theres nothing left