Hello to everyone, I just purchased my first ram. It's a 1994 1500 2wd v6 3.9l magnum. Im a heavy duty mecanic so I kinda know were im going. But this problem is pissing me off! ok, so when i drive the truck its all good, the idle is a bit spitty at times, it goes low, when the engine starts getting warm the check engine light goes on and it starts running all fu#$%ed up. When I kick it it drives fine, then when i drive it normally it gives jerks, then when its idling it wants to die. I kept the truck idling and popped the hood, it sounds like a vacuum. Its wierd as hell. The fuel pump is making a winniy noise also. Im suspecting its the fuel pump, but the engine code is giving me 21, thats the o2 sensor. So any help would be great, thx

 

o2 sensors can do that. i'd say, in this instance, the computer is telling the truth. but then again, when has it ever lied to us? lol

 

well if you have an o2 sensor code then u prolly need to replace ur o2 sensor. the o2 sensor determines the air/fuel mixture and it it is bad it wont give the engine the right mixture and make it run rought. that would be the first thing i would do

 

if I remove the 02 sensor and cap the hole, and by-pass the conector do you think that would work?

 

you can just get a spark plug non fouler and screw into where the o2 sensor was and then screw the o2 sensor into the non fouler. it will keep it out off the direct flow of the exhaust and keep ur service light off

 

Just replace the sensor first, then worry about non foulers and other things if it still won't work. You need a sensor in order for your truck to run correctly.

 

Also, the sensor you'll be replacing is the one before the cat, the one that is closer to the engine.

 

yeah, guys.....which o2 sensor? if its the front one, then yeah, replace it. if its saying rear, then its prob a bad cat.

 

ill start with changing the o2 sensor, ill keep you guy's updated thx