So I just bought a 3 owner 04 F-150 Lariat(pictured below) with 150k miles for what I thought was a good deal at 5k even. Dude told me it was alittle rough on the road and I didn't think anything of it but when I took it for a test drive it took off just fine but after I took my foot off the gas and was just about to put it on again the truck stated to stutter like I really don't know how to explain it other wise almost like it was trying to push itself forward but was having a little bit off a rough time... hopefully just a dirty injector(praying) I didn't think it was the trans because the revs weren't all over the place but I'm no mechanic some help or advice would be nice please

 

Awesome deal... 04-05 Larry 4x4 with 140k miles for $5K.. you just may need a tune-up.. was the CEL flashing when that happened ?

 

No it was not

 

Do you have any Maintenance records ? when was the last plug change ?

 

The last owner said he changed the plugs a few months prior to putting it on Craigslist

 

Do you believe him ? lol

 

Ummm that's a good question ha, ya he seemed like a decent guy. He just put a whole new exhaust system on from manifolds to end cap so I would say he's a trust worthy person in regards to the work he did

 

So.. at least he got the bad OEM plugs that break swapped out for you. Good deal. I wonder if he used motorcraft plugs.. if not that could be the problem.
Another thing you will need to check is the FPDM under the spare tire..

 

So I just got it back from the shop and they said it was an O2 sensor... never heard of an O2 sensor causing anything like that but they didn't tell me what sensor it was so I don't know what one it is... typical shop

 

How do they know.. must of been a DTC stored in the computer. Read the codes. Some auto parts stores will read them for free..