Hi, I just bought (2 months ago) a 2004 Ram 1500 4x4 with the 5.7L Hemi in it (all stock). It has 22k miles on it and it ran like a top when I first bought it...had crazy power and I would spin the tires on accident just pulling away from a light. Now, all of a sudden, the power seems to be crap (hesitates off the line, decreased acceleration) and I have no idea why. Air and fuel filters are new. The check engine light did come on the other day...code came back as P0157..low voltage on O2 sensor 2, bank 2. I cleared the code and it hasn't come back after 100 miles of driving. Do you guys think this could be part of the power loss problem?

Also, does anyone know of any good realtime engine monitors out there for the 5.7? I'm looking for something that will give me detailed engine performance info.

Thanks in advance!
Ryan

 

Dont know if it helps, but try changing the spark plugs. I've read, (on this forum actually), that people are needing to replace them before 30000 miles. If the plugs dont burn all of the compressed gases, its next thing to pass out of the exhaust manifolds is the o2 sensors. It might help, and cant hurt! As far as engine monitors, I have no clue. (hey I'm honest)

 

A friend's seemingly identical truck has much the same problem, except no "check engine" lights and his dealer is completely stumped.

However, the latter is no surprise since the service writer/manager assured me that '05 Rams never came from Dodge with a 3.92 rear end and that if I really had one in mine (special ordered with same, btw) it HAD to be aftermarket. SHEESH! He was so sure he marched me out to a pair of mechanics to "show me." And, he called ME "pissy" when I ended it by saying, "I told ya so." Really... Unfortunately, this guy seems to have identical sibs all over the country! I strongly suggested my bud take his truck elsewhere.

Best of luck and let us know how this plays out.

 

I would also say to change the spark plugs.

 

O2 Sensor would definately cause your problems. Happened to my Jeep TJ before! There was no power and It would just about stall everytime I tried to accelerate. I would get it changed if I were you!

 

Yup... I had a 1996 RAM with a bad O2 sensor and it really amazed me how much a small little thing like that could affect the entire truck.

 

Thanks for all the input guys. I'm going to look into the O2 sensor further...the engine light won't come on again so i'm not sure what the deal is. Anybody have any idea if the sensors can be tested for proper resistance, etc to see if they are bad or not?

 

I'm pretty sure that bank 2 is the O2 senser after the cat.