Ok, I have an interesting problem here. I've done the search and I can't find anything like it.

For starters, I have a 1998 Dodge Ram 1500 4x4 with a 360 and an auto trans.

When I started my truck, it showed 5/8 full. Then, suddenly, the fuel light comes on and the tank reads empty. Then it's 5/8, then it's empty again. Finally, the gas gauge read full and it quit acting up.

Also, while the truck is still cold, she idles rough, and I can hear a massive sucking sound coming from the engine bay. The engine also idles rough and doesn't seem to be making any power until it warms up.

The CEL has not come on at all.

Could this be water in the fuel? A vacuum leak? Any advice would be MUCH appreciated.

Thanks!

~oz

 

sending unit may be crapping out

have you had the intake tube/hat off latley? i took mine off once (this was years ago..before the 4 different intakes ive gone through) and didnt seat it right and had a 1/4" gap on the back side i could barely feel with my fingers.. had to use a mirror to really confirm it.. ran the same what you described untill i reseated it

could also be a vacume leak.. start trying to trace down the source of the suckin noise

id through in a bottle of fuel inject/system cleaner and a some dry gas or stabil or something to remove the water in your fuel.. (if there is any.)

 

Well, the CEL came on earlier - I had the code scanned and it turned out to be the fuel level sensor and one of the O2 sensors. My question is this: will I have any issues if I replace the O2 sensors without replacing the cat?

 

Please don't just start throwing money at it. If you have a vacuum leak the computer will try to correct it by enriching the fuel mixture. If it's not able to do it the O2 sensor will pick up on the mix problem and set a code. That does not mean that the sensor is faulty; only that it "senses" a mixture problem. Find the leak 1st, then reset the comp. and recheck.
On the surface it sounds like a fuel pump/filt/sender problem...maybe starving for fuel. A poor fuel delivery will cause the TB to suck harder possibly giving you the added noise. (if you've ever heard a dying engine JUST before it croaks; there is a really pronounced inrush of air through the TB/carb.) I would be looking at the fuel pump/delivery system 1st rather than replacing sensors.

 

Understood. I'm just wondering, though: now that the engine has given the sensor code, will the O2 sensor still be bad even after I have found the problem and fixed it?