Hello, I'm new to this so bare with me lol.. I have a 01 ram 1500 5.9 that has lost most all its power from a stop to 2500rpm then it goes like normal, sometimes it has a small backfire in the intake when starting off. been fighting this for months now.. Things I have done to try and fix this problem are.... 1. Changed the plenum gasket to the huges plenum plate kit. 2. New cold air intake. 3. Checked all vacuum lines. 4. New map sensor. 5. New IAC. 6. New plugs, wires, cap, rotor, coil. 7. New fuel pump. 8.Hollowed out the CAT last year but in doing so I had to unplug the O2s and it ran perfectly fine up until a few months ago. Engine has just under 200k, could a partially clogged muffler cause this? TPS? Idles consistently at 600rpm, live data shows the timing jumping all over from 9-20 adanced, vacuum shows 15 steadily and at 2500 rpm it stays at 20. Don't have a compression tester to check that, only codes it shows are the 02 sensor codes, no missfire code... Thinking dynamite is the only fix, hoping not a flat cam lobe.

 

Does it make any rude noises? What does TPS have to say for itself at part throttle?

If the muffler was plugged up, you would have troubles in the higher RPM range, and less at idle/part throttle....

 

Doesn't make any out of ordinary noises, I was thinking the same about muffler, I haven't had an ohm meter on the tps yet, rpms don't jump when ideling so figured it was good yet. Pickup runs good at idle raps out fast just becomes a dog when I try to take off. Still shifts through all the gears

 

If you unplug the 02 sensors, does it get any better? Or are they still currently unplugged?

What brand fuel pump did you put in?

 

Yes are currently unplugged, after gutting the cat it ran wayyy to rich because I forgot to unplug but after i did unplug them it ran fine until now lol.. Also I put in New injectors. Could it maybe be the cam sensor or crank sensor causing this? Seems it has to be something with air/fuel mixture or timing.. I'm stumpped

 

If it isn't giving you misfire codes, then the crank and cam sensors are likely doing their job. I would wonder about fuel pressure.......

 

Smells like fuel, running to rich it smells like, fuel pressure is at 49psi

 

Do you have a scanner available? If so, see what temp the PCM thinks the engine is.

 

Update: well, tonight I hooked up vacuum gauge, it read 15 at idle, 0 under a load while backfiring. Hooked a new fuel pressure gauge up and it read 32psi at key on, 31 at idle and same under load but when the key turns off it immediately drops to 5psi. Could this be a fuel pressure regulator and IF its vacuum driven could it be a vacuum problem not allowing the fuel regulator to build enough pressure? Or maybe it's electrical I'm not sure. Could the crank sensor retard the engine enough not to build enough vacuum? Haven't found any vacuum leaks anywhere yet, maybe it's between the tank and the intake Idk.. Hoping just 1 thing fixes all, tired of dumping money on parts that don't make a difference. Any thought would help out a lot thanx

 

Fuel pressure is not vacuum regulated. You need to replace the fuel pump module.