I am still getting same problem with my truck that I had that made me replace the motor minus tapping in motor that was bad... I am geting codes p0171 p0174 and it lopes while idleing and has no power to even spin wheels in loose gravel... The dealer had my truck 3 days before and told me they couldnt figure out what was wrong and that the motor had a bad tap in the top end so I found it cheaper to replace the motor with a used motor with 93,000 miles on it. I get in it today its doing exact same thing as before. I talked to a mechanic friend that put my motor in he seems to think the computer could be bad or that my fuel filter may need top be changed since its running too lean . The gas when u press it half inch takes off fine but if u try and stomp it it sputters and eventually catches up and takes off...Any suggestions.... HELP... S.O.S. I dont want to get nickeled and dimed to death.

 

you have a vacuum leak probably. the most common cause of those 2 codes is the rubber elbow at the back of the throttle body thats to the PCV.. they get old and crumble.

 

Clean the MAF sensor, change the fuel filter and check for vacuum leaks

 

What should I use on the mass air flow sensor

 

MAF sensor cleaner. There is a how to around here do a search. CRC makes the stuff.

 

I cleaned those things out it ran better for about 5 mins then back to same crap.. I did change fuel filter and it was dirty looked like mud water coming out of it... Do you think it clogged and messed the injectors up? Is there a way to test injectors?

 

run techron in the gas. did you look for the vacuum leak at the PCV elbow on the throttle body?

 

Did you reset the pcm by disconnecting the battery for 15 mins or so?

 

I did check the hose theres one on the top that goes to something over next to the firewall that was iffy but it wasnt on the back of throttle body... No I did not reset the pcm maybe I should try that. But funny thing was is when i started it up the check engine light went off... then after 5 mins running good it came back on.

 

The pcv valve hose would be coming from the passenger valve cover, the pcv valve. It routes to the very back of the throttle body and was known to crack in the very back. in your case, it may not be hooked up... forgot during the swap? needs to be checked. it is the most common cause of a lean condition, which is what you have. most likely a vacuum leak.

Lets take a step back. What year and engine was your original, and what did you put in it? Did you use your old injectors, ignition etc...?
Your previous engine had a p0171 and p0174? If so, you have to look at things you are using from your old motor that would effect both banks. Typically not a specific injector, unless they are clogged on both banks. Things like FPR, MAF sensor, vacuum leak in the pcv system, clogged cats etc..

 

You may want to drain the gas tank and clean it out........

 

original motor is what came with the truck 1999 and I had a shop put it in and yes they did use my old injectors and fuel rail. I did have clogged cats and replaced them. Then shortly after replaced my motor. Would the computer tell you if the cats were clogged?

 

Not necessarily, but a muffler shop can test the cats for bloackage.

 

I drove the truck for about 20 miles after resetting the computer... It drives ok at time then others not so ok. If u lightly depress gas it sputters but if u stomp it most of the time it runs like a scalded rabbit... I drove it tonight and stomped it and it shot out red hot embers I think the cats are partially clogged because they werent totally glowing red hot...

 

Cha ching

That is premature failure, if they have been replaced recently like you said. Most likely caused by the lean condition