(By the way I searched for this and didnt find anything on it!)


I went muddin the other day, and ever since my truck has been running wierd. When you first start it up, it runs great....but you let it run for about 5-10 mins, the exhaust note gets really low, and the engine starts to vibrate the whole truck. Also when you take off from a stop to get it going without the engine bogging down, you have to literally FLOOR the gas to get it going. It does this through all the gears, only when accelerating.

I have found a sort of easy way to correct this...if you just floor the gas pedal, and drive all through 1st, 2nd, and 3rd, (just a note, I didnt know that my truck can chirp its tires in 2nd gear ) it corrects this problem. It runs fine as long as you dont turn it off and let it sit for a while, like overnight or during work. Then once you start it up after its been sitting for a couple of hours it does this all over again.

I know its not any of these cause I just had my sparkplugs, rotor, cap, and wires replaced.

For some reason I think that the problem is my catalytic converter...it has just been on my mind. I was reading the other posts and I saw that a smell of rotten eggs can be a sign of the cat going bad, and I smell something foul every once and a while, but I always thought it was mud burning on my exhaust.

Please help me!!

 

whats it idleing at

 

Dont know? I dont have a tach, just normal idle it runs horrible, unless i get out and floor the gas pedal, then it stops, it feels like something is clogged, but I have no idea what it could be!

 

i have this same problem some one help us

 

Like I said in Yotamasters thread. I would check your AFM. Once your engine comes out of closed loop you really notice the problem. When you floor it you are drawing the flap open a lot and getting it past the stuck position.

 

this happened to me, i did the same thing you did replaced spark plugs, cap and rotor, wires, coil. none of those worked. then i went to the junkyard and got an AFM and it worked like a charm. autozone wanted 225.00 for one, but i picked one up for 60 at the junkyard. good luck!

 

AFM sounds like the ticket. But you may be right about the cat. In my 99, I went through some mud, got a CEL, and it was the cat. It ran pretty rough in the first few minutes of starting it up, then would smooth out. The cat was still under warranty, once I got a new one, no issues whatsoever.

 

would it help to just take the cat off and hollow it out?

 

Well, they're on there for a reason. Running w/o a cat could throw a CEL, and cause backpressure issues.

 

dude are you just lookin for an excuse to punch out the cat? your afm probabally has a stuck flap like said above, you can clean it with compressed air and then spray a little wd 40 on it, no need to get a new or used one if you can easily fix yours.... just my 1/2 a cent..the check's in the mail

 

i have close to the same problem but it stutters only when i try go but it idles fine. when i reach 3500 rpm it takes off like crazy i have been working on it for 3 days straight and i cant figure out what is wrong with it. somebody help plz

 

Just to let you know a "rotten egg" smell is no indication that your cat is bad, it just means that the fuel you are running is high in sulfur. If the cat was bad and was plugging up, it wouldn't let you accelerate as the engine has to not only breath in but also breath out to run. You would most likely find that it would fall on its face when trying to accelerate from a stop rather than "chirping tires" if your cat was bad.

 

If you were to hollow out the cat it would actually run worse as the secondary O2 sensor would find to much unburned fuel and would lean out the engine also throwing a code. Now if you were to use a dummy o2 sensor that fools the computer into thinking everything is fine, then that would be different.