CEL on loose gas cap, VSC OFF

[tcpoob]

Have you had to jump start the truck a lot lately?

the 2005 V6 4WD has never ever needed jump start.

on service history, engine oil was changed every 5k to 7500 miles using mostly M1. spark plugs were replaced in 3/2010, at around 90k miles on odo using Denso from Toyota dealership. I am attaching a picture of those original plugs that had 90k miles on them. I realize it's overdue again using the 30k interval suggested officially. Could this cause the intermittent blinking CEL and rough start/violent shake on the 1st start ? Does does it point more to potentially leaked coolant hence head gasket issue? I know w/o code we are just speculating. I'll try to nail the codes down at the dealership or somewhere. I have an appt schedued with Toyota for later this week. But are overdue spark plugs something I should pursue? I can and will replace them but I don't know if i should do it now given the issues I am having. (yes it's overdue per maintenance guide and it's in my todo list, sorry).

I didn't find any reference on "valve adjustment" in the offiicial maintenance guide. Toyota Parts and Service. I picked 4Runner, 2005, and clicked through the schedule every 5000 miles.

Thanks and have a great vacation. I attached the original spark plugs, changed out in 2010, at 90k miles ish, for your review. Do they look aweful and should have been changed much earlier?

 

[tcpoob]

P0306 dtc

Autozone found 1 code : P0306
Cylinder 6 misfire

So now what - have a compression test done to confirm if it is a blown head gasket ?

My spark plugs are quite a bit overdue based on the 30k schedule. Should I try replacing that to see if the problem corrects? I've Denso on, not the fancy Iridium plugs.

Does this sound more and more like the infamous Head Gasket issue?

Thanks

 

[BlackWorksInc]

Could be, but I would try and do a compression test (also do a leak-down test if you can) to just get that out of the way. While you have the plugs out go ahead and replace them with new ones (make sure to check the gap.)

 

[tcpoob]

replaced coil on #6 and 5 of 6 plugs with ngk Iridium IX (can't get #1 plug out, it loosened about a turn and became really tight that I got scared and gave up, any tricks? ). new car battery. so far so good knocking on wood... thx

 

[tcpoob]

The damn code P0306 came back after new ignition coil and all new plugs

replaced coil on #6 and 5 of 6 plugs with ngk Iridium IX (can't get #1 plug out, it loosened about a turn and became really tight that I got scared and gave up, any tricks? ). new car battery. so far so good knocking on wood... thx

unfortunately, check engine light came back on today along with VSC TRAC ...

scanned it, P0306

so i am guessing it wasn't exactly a problem in the #6 cylinder coil because what's there is a new one.

I started a new thread as this one has the "loose fuel cap" subject which is misleading and I don't know how to / if I can edit thread subject. new thread tracking this is here, thank you