How to spend $400 on a $40 part......sort of.
the check engine light came on, and the the rough idle started. i think it was in that order - and that should have been a clue.
Figured it had been 80k miles since the last tune-up - probably needed plugs. so picked up a mid-priced plugs ($36) for my
2003 envoy with 4.2L - no need to pull the codes, its just going to tell me it is missing....maybe even tell me which cylinder.
NBD - grabbed a new air filter also.
the 4.2 is an inline 6 cylinder DOHC design in a vertical orientation - meaning the cylinders move perpendicular to the ground.
The spark plugs are straight down from the top - and each plug has its own coil pack, so no wires to fail. the problem is that anything
falling into the spark plug well, goes down the spark plug hole.
the front coil pack is removed - see the hole.
so i'm 30 minutes in, and have the front 5 plugs changed, and coil packs re-attached.
(i also found that the valve cover gasket is leaking into the plug wells, but meh - that will burn)
as you can see - the back plug has a bit of a challenge to it - but the tool collection is strong here.
i get the spark plug socket over the plug, and fish a short extension in, then drop the ratchet handle on -
the plug will not move. remember i don't want to break the plug, cause the ceramic chips could fall in.
I get an 18" long 1/2" drive breaker bar and get the plug moving - it's going, but it is tight - way tighter
than it supposed to. i have my ratcheting torque wrench, and there is enough room to get 1 pawl to engage,
and it is a struggle. Check the internet, and this is common - but why just one - we'll i'm thinking the last time
something was wrong, i had the dealer do the plugs - so they either didn't do the back one, or didn't use anti-seize -
by the look of the plug, they skipped it. Also put out an sos to
@extremedave - see what he info he had.
Dave's advise to let it sit with the liquid wrench, and rock it back-n-forth a bit was a winner. plug was out in 5 minutes this morning.
I button up the resonator (i think its a resonator) and fire the car up - still running rough. I quick internet search says everyone
replaces the coil packs on these cars around 200k miles (i have 205k, and it is 15 years old next month) - so i purchase a coil 6-pack ($250)
and replace them - fire it up, and it is running about the same. figure i need to take it for a little longer drive, so i put about 10 miles on,
and stop at autozone to pull the codes. it throws something about the cam and crank sensors not happy - the solution is a VVT solenoid.
(variable valve timing solenoid) - autozone has one, $40.
other than having to remove the power steering pump, it is a simple swap - less than 15 minutes.
fire it up - still running like crap - so i'm thinking cam position sensor (or crank position sensor) - or maybe i got a bad coil?
run back to autozone, and get the new codes pulled. Misfire on #1 - well the #1 position has a wiring harness going over it, mounted in a solid channel.
it is interfering with the placement of the coil pack - so i take my time removing and replacing the #1 coil pack and re-seating the electrical connection.
and fired it up.
purred like a kitten. in the end, it took about 5 hours, and over $400 - it was probably just the solenoid - although it was time for plugs.....
typical 80/20 rule - 20% of the problem will take up 80% of the time.....
now it is time to get the 4wd back on-line, and if that doesn't cost anything, maybe i'll get winter tires, so that
@gtluke's family can feel safe.
