If this is the same Techron I use it is made specifically for cleaning injectors with seafoam being more of a all around cleaner, Techron seems to be stronger and faster acting as well but I usually double the dose if a real problem but as a preventive measure I follow the instructions. Techron works great on motorcycle carb small orfices as well, been using it for 12 yrs. now.

 

this truck is starting to **** me off. its one thing after another with this.
ran the truck again and it threw the code for cylinder #4. swapped injectors from #2 to #4
luckily it threw the code again it was for a misfire #2. well thats sorta good news. BUTT
now i hear a vacuum leak more from inside the truck than out and last night and this morning it had a higher than normal idle. still hear vacuum leak. well on the way home the idle went back to normal but still hear vacuum leak. it seems to be one thing after another

 

Check gasket at airbox and TB.

 

Check the vac lines. You might have broken one, since they are on the side you were working on.

 

this truck is possessed. drove it a bit today. had misfire can feel it. didnt clear code yet. so still had check engine light on. heard vacuum leak. then all of a sudden the check engine light goes off. runs good and no vacuum leak!! havent had time to diagnose vacuum leak yet. will later today

 

Check and see what code you are getting. Could possibly be there as stored code. Sounds like a misfire and vacuum problem. May not be connected, could just be coincidental.