Spark plugs, vacuum leak, 02 sensor problem

So I recently picked up this beautiful 2004 T4R Limited 4.0 motor with 6k on rebuilt original motor with paperwork.
First weak of ownership I get VSC light cel I’m like dam just my luck. Turns out it’s an 02 sensor so I replaced sensor and clear codes. Then I noticed as winter set in I get a stumble if it’s not 100% warmed up in the morning like it’s got a vacuum leak or something. Along with the heating not defrosting unless I rev the motor. I just can’t seem to catch a break with vehicles I swear. So I popped the hood on Saturday morning because I have to get this thing right I mean I just bought the rig 2 months prior and spent a pretty penny on it. Overflow bottle is above high mark take radiator cap off and can’t see coolant. So pull out my burp funnel and fill it up 20 min later air bubbles out and problem solved. Sweet 1 down. Time for throttle body cleaning right away noticed rear vacuum Line not hooked up alright this may be it. Cleaning throttle body inspect everything find cracked pcv hose easy fix done. Close the hood thinking I’m good. Test drive now it runs even worst with hesitation while driving. I decided to reset ECU maybe it needs to re learn since vacuum and hose leak. Sunday morning get up starts up and same hesitation but at least my heater is working excellent now. So I say screw it go down pick up some new NGK spark plugs pull out plugs that were replaced with rebuild Denso Toyo plugs they looked good except for 2 had some discoloration on the white part, whatever gapped to 44 pooped them in and test drive. Finally I test drive it and wouldn’t you know it it run’s amazing. Rig now has 10k on rebuilt motor and is running very well. So that’s my first experience with a T4R and I really love this thing I just hope it can be reliable for years to come.

 

welcome, sounds like you did a good job of fixing everything up. Should be very reliable for years to come.