Newbie Maintenance Help

[gaterose]

I bought my '03 limited v6 from my aunt about a month ago, with the exception of the most recent oil change she has had the dealership perform every maintenance on it. She took excellent care of it and had it since it was new. It has 120K miles and the maint light came on and her sticker said it was due in another 300 so I decided to change it. I looked up the maintenance schedule and it said it was also time to replace the spark plugs.
So I went to advance, bought 6 qts royal purple 5w30, K&N oil filter, and 6 denso iridium spark plugs. I came home changed everything (as I've done on my old truck and other vehicles countless times. When I started it the TRAC OFF, VSC TRAC, and Engine light were on. I tried to manually reset the lights by tripping the ODB sensor as I read in a thread here, but that only worked for a little while. So today I went to advance had them run the ODB and they said I was getting a signal that said both sides were running too lean and they thought it was a spark plug; they also cleared the lights.
On my way home I noticed the engine seemed to be loping at idle, sometimes almost killing out. I came home and made sure the plugs were tight, then eventually put the old plugs back in to see if a new one was bad for some reason. Nothing seems to be helping and it definitely wasn't loping before the plug & oil change. Any ideas what it could be?

 

[CJ3Flyr]

It's an '03


Just guessing: While doing the plugs you pulled or split a dry rotted vacuum line. I'd be inspecting all the rubber hoses (particularly on the drivers side). It sounds like maybe you have a vacuum leak.

 

[gaterose]

WOW GREAT GUESS! A million thanks! I don't know how I didn't think about that, I have an old wagoneer that did the same thing because someone decided to remove several vacuum hoses before I bought it ($250 was still a good price though).
It was one of the back hoses that goes in under the engine cover, it looked like it was still connected until I wiggled it. I feel stupid now.. Its an 03 but none of the hoses are dry rotted, they are all still soft & new feeling, in fact the entire engine compartment looks almost new..THANKS!

 

[cleger]

Yeah my 4Runner is an 03 and has 198k miles on it now and is super super clean under the hood and everything is in good shape.