JonxSmith

Sorry if this is long winded, I need help, and I'm pretty thorough..
I bought a buddies 2000 Silverado 1500 4x4 about a week ago.. He only wanted $5000 for it, 4.3l 5spd with 89k miles.. I was looking for a 4x4, while I wanted an extended cab.. I couldnt turn it down.. Now, regretfully, I'm running into problems, and need some help lol.

It has the usual extremely noisy release bearing, but whatever, new clutch is probably on the horizon. But for the standing issues..

The ABS and Park Brake light comes on randomly, and there is NO abs.. Wheel speed/ABS sensor?

My fuel gauge reads erratically, from full to empty, but when in limbo its pretty close to right, I have the sending unit, just havent put it in yet. and heres why:
I drove the truck, never having driven a 4.3 manual before.. and didnt notice anything weird. after getting to know the truck a bit, on acceleration it seems to stumble a bit.. idles and revs fine as far as I can tell.. When at lower rpms I dont or havent noticed it, whether its there or not, but when going from a cruising rpm and giving it throttle to accelerate it stumbles, the best way to describe how it feels is its like its cutting fuel or running rich, then it takes off again, and does it again, it does it about every time I get on it, but the severity and the repetition varies. I changed the fuel filter today, sprayed the throttle body, cleaned the EGR valve, cap and rotor, and nothing. After doing that and not fixing it, I went out and beat on it, like a good pissed off mechanic would do, and I found that its fine on light throttle, and when I stand on it, it seems to be the most consistent when its at 1/2-3/4 throttle.. Before I bought the truck it had new plugs and wires put on it..
My buddy suggested rebuilding the throttle body or adjusting the timing, but it seems too inconsistent for timing..
Any ideas or input on any of this? I figure I'm either looking at injector trouble, or a fuel pump issue, but I am new to the world of 4.3s.. Was my friend right? or does anyone else have experience with this problem and can give some input?????



Apologies again for the long windedness, thanks again,
Jon Smith

JonxSmith

If it helps anyone who might view and wanna give any input.. After cleaning the EGR yesterday it threw and engine code, I went and had it scanned and it turned out to be the o2 sensor throwing the code.. Could it have just been reading right on the brink of throwing a code, and after beating on it it finally threw it? Could that have been causing my problem?

Chuzz

I'm not a mechanic, but I'm pretty sure that a faulty O2 sensor can cause a stumbling problem. It will cause the engine to run rich and that in turn can foul your spark plugs. Have you pulled your plugs and looked at them? If not, you may want to do so. Also, cleaning the TBI won't hurt any. Get a can of throttle body cleaner and follow the directions. It seems that regular carb cleaner can strip the coating off of it.

JonxSmith

Just went and checked the plugs, they seem fine, of course they aren't even 2 weeks old.. I did what I read in a post (might be stupid for doing this) to disconnect the 02 sensor and let it run on a stored type of fuel map/timing. I unhooked all the 02 sensors and took it down the road, and it did the same thing, except this time it flat fell on its face, and basically didnt want to get out of its own way... If unhooking the 02 sensor makes it run on stored fuel maps, and it still fell on its face.. Does this mean I have a fuel/intake issue??
My luck is AWESOME, buy my first full size, has less than 90k miles, and I've spent more time trying to get it running properly than I have driving it.. HOOOORAY =)

Thanks for your input chuzz.

JonxSmith

Well, no help from anyone for the most part, but for the sake of anyone finding themselves with the same problem I had. I searched random forums for hours trying different things out to fix the truck. Finally I ran across a post that someone had the same problem and done all the BS I had done to fix it with no success.. Turns out, it was my MAF sensor the whole time, I took it off, cleaned it EXTREMELY carefully, got all the carbon off of the 3 little wires in there, put it back on, and PRESTO, felt like a brand new running truck.