07 Taco TRD sport v6 rough start

Have had my 07 taco for a couple of months now. Has been running great but recently it starts a little rough after sitting for a while and it seems to have been getting a little worse. I have a few ideas of what it could be but would like to hear what you all think. Thanks!

 

Mileage? Remember, Tacomas do not have iridium plugs and therefore need changed every 30k. I personally ran mine accidentally for 60k with no issue and I have heard of guys running 100k. I also run a bottle of Techron through every once in a while, it can't hurt. I am however not a big Seafoam fan.

 

It has 170k

 

When is the last time you put plugs in it? When was the last time you put a PCV valve in it? I traded my 06 in with 175k and quite honestly it ran as smooth as it did when it was new. It should not be running rough.

 

Do you have the maintenance records? If so, check and see if the plugs have been changed recently. If not, that'd be a good place to start.

 

Could be a bad head gasket, iirc there were a few reports of earlier 1gr-fe having a weak spot in head gasket. I think it was reported to cause a misfire on Cylinder 6. I want to think they changed the head gasket design sometime in 06, not positive on that though.

 

If it is a four cylinder it would have iridium tipped plugs.