Hello there!
So I've been looking for a truck for weeks and either found junk for a bunch of $$$ or by the time I'm getting to the dude's place it's sold...
Found this one couple days ago 2004 four doors, HEMI 5.7 with only 120k miles for decent money, but it's got the check engine light. The owner says he went to AutoZone a while ago to get it checked, they read the code P2175 so he's got the throttle body but didn't replace it.
When I hooked up the scanner it read p0171 and p0174 as only active/ pending codes. However replaced the throttle body and cleaned the air sensor on the intake box with disconnected battery. Relearned the TB, went for a ride and after 15 minutes it gave back the check engine light and same codes. The truck runs fine though, no rough, no stalling, stable RPMs.
Could it be a fairly simple fix or rather not think about this truck and continue looking?
thanks!

 

Eh, I would not even bother personally speaking. Sounds like it's gonna continously have problems.

 

How's fuel pressure? How old are the O2 sensors? What does system voltage look like?

 

Check air filter as well , and if it as an aftermarket setup could cause issues , and 02 sensors can cause issues,,vacuum leak around intake ,,

 

Too late, already bought it. Worths the risk in my opinion.

 

Dude's got it at insurance auction six months ago from Oakland, CA (I'm in Sacramento area) and as soon as he got it he replaced all filters and fluids, brakes and struts, he prepared the truck for himself. Nothing else known about previous history.
Last night ordered on Amazon new copper spark plugs and wiring, injectors o rings (usually I'm cleaning the injectors in the ultrasound bath), intake manifold gasket, throttle body gasket, EGR valve gasket, MAP sensor, air charge sensor, PCV valve. Today I've got two cans of Pennzoil Platinum synthetic oil 5W30 and a Mopar oil filter. As soon as I have all the parts will replace and clean all that stuff.
According to my google research there are three more things that can cause those codes- EGR valve, O2 sensors and fuel pump. Will have to look for a fuel pressure tester to test that as well.

 

Have to get a fuel pressure tester. Voltage is about 14V on running engine. O2 sensors unknown yet.
Weird thing, this morning drove few miles with the gamily and the check engine light went off. Couple trips later came back on though. Was idling for about ten minutes, that's when it lighted back on and the engine became louder (I think).

 

I hope you didn't overpay

 

You tell me. Paid $3500, asking price was $4900.

 

I think that's an awesome price. When I had my truck I paid $3200 for it. It was an '02 4.7 Short Bed with a Regular cab though. I had to sell it for $5200 since it was going to start to cost me too much to fix it up. I was lucky since I theoretically broke even, but it was a shame since it had no rust and looked fantastic overall