Hey everyone well this problem has been going on for 2 weeks and it seems to have stumped me and from my research from this forum I'm still lost. I have a 2005 XLT 5.4 auto tranny. The truck started acting weird and the motor starting loosing RMPs at idol.. It also sounded like it was backfiring every couple seconds so I took it to the shop and they told me that I had a misfire in cyl 4 and pretty much need to change the plugs and a new coil for that cyl. So my friend that is a mechanic swapped out the plugs and coil and wiped out the codes and it started but sounded and acted a little better than it did. Now I'm getting code P0172 and that's it. Truck drives nice but while at idol it still losing RMPs and still vibrating. I'm almost out of money and over having these issues. So what I'm getting at is I know that alot of people are having these issues just wondering if anyone had solved it and maybe has a checklist I can go through to try and narrow my problem. Thanks for reading this but I wanted to explain the whole situation. Oil change done air filter done new plugs and coil on #4 and used decarb to clean the injectors. Any help would be appreciated....

 

Check for vacuum leaks.

 

Ok I'll check on that when I get hm. Anything else i should look for?

 

Stuck open injector on #4 was the culprit

 

Change the oil, then. A stuck open injector will flood the cylinder and fuel will wash past the rings, diluting the oil. If you don't change it, a spun bearing may be your next problem.

 

Ok thank you getting done today