4.2 hissing sound
#1
08-27-2015, 12:49 PM
4.2 hissing sound
My 99 4.2 has P0171 code and I was checking for vacuum leak and found the elbow underneath of the intake was bad so I replaced and the light is on again with same code..now I can hear an hiss at front of engine that only last for a few seconds so what is your guys idea?? Btw my intake body is aluminum (UPDATED) I removed the PCV when Truck was idling and cover the valve and didn't notice any rpm drop should I change the PCV?? It's not OEM it is Purolator
Last edited by Mrmarcio02; 08-27-2015 at 04:20 PM. Reason: Updated
#2
08-27-2015, 10:12 PM
I would double check the hose you just replaced, from what I understand that is a tight fit to get to that hose and maybe you curled an edge on the hose when you put it on. You may also have a bad hose on the PCV, remove it and inspect it for splits or soft spots.
An exhaust leak close to the O2 sensor can also cause that code, but that wouldn't give you a hissing sound. Take a look at the brake booster hose too.
Good luck.
An exhaust leak close to the O2 sensor can also cause that code, but that wouldn't give you a hissing sound. Take a look at the brake booster hose too.
Good luck.
#3
09-07-2015, 07:50 PM
I would double check the hose you just replaced, from what I understand that is a tight fit to get to that hose and maybe you curled an edge on the hose when you put it on. You may also have a bad hose on the PCV, remove it and inspect it for splits or soft spots.
An exhaust leak close to the O2 sensor can also cause that code, but that wouldn't give you a hissing sound. Take a look at the brake booster hose too.
Good luck.
An exhaust leak close to the O2 sensor can also cause that code, but that wouldn't give you a hissing sound. Take a look at the brake booster hose too.
Good luck.