Very Rough Idle

[3A703]

My 01' has just started Idleing bad, I can push on the Fuel pedal and at about 2000 RPM it quits, then runs very poorly again. I just changed the fuel filter and no improvement. Any Ideas??:confused:

[DmaxMaverick]

Check your engine oil level! If it's good (look very closely), check for DTC's. Is your SES lamp on?

[3A703]

Oil Level is ok, SES light is not on and there are no DTC's

[3A703]

So, tonight I crawled under the truck to see what in the world is going on and noticed that the fan looked a little odd. On the dampner pulley there is one big bolt instead of 4 like I am custom to seeing apparently the rough idle problem has caused this bolt to loosen and came out putting a nice groove in the fan blade. I tighted the bolt the best I could started the truck and no change. Still idles very rough and just rund like crap, shut it off, and the bolt was loose again:mad:.. Does anyone have any ideas?? I am about to drive this pile of Chevrolet off a CLIFF!!!:rolleyes:

[3A703]

It appears that not to many people read these posts! But if there is sombody out there that does. I am looking for the torque that is required for the dampner bolt. For some reason mine came out?:confused:

[DmaxMaverick]

I'm not sure where to go from here, without some electronic diagnostic data. You need to check the balance rates and PWM at idle. This can be done with a Tech II (dealer$hip, or a friend who might have one), or a Predator programmer (any 01-02 will work, regardless of what vehicle it's locked to). Report the results and we may be able to help with what's next.

The balancer bolt loosening is odd. I (and the manual) suggest replacing the bolt with new. There is a specific procedure for torquing the new bolt to prevent loosening. If the bolt has been R/R'd, it probably wasn't tightened properly, and the manual warns of loosening if it isn't. If the belt was on during tightening, it won't tighten properly.

If you don't intend to replace the bolt, for now, I suggest this:
Remove the belt (relieves lateral tension on the pulley).
Remove the bolt and clean the threads.
Apply blue Loc-Tite to the threads.
Torque to 240 lb/ft.
Allow the Loc-Tite to cure 12-24 hours before starting the engine. Install the belt.
At your soonest convenience, replace the bolt with new and follow the installation instructions to the letter.

[3A703]

DmaxMaverivk, Thanks for the advise I will see what I can do. Just another quick question do you think the Injection pump could be causing this? I plan on replacing the CP3 soon, I beleive it is causing the P0093 code I keep getting? I have replaced everything under the hood with the exception of the pump it's next! It runs like a gas engine Dieseling!! if that makes sense..:confused:

[DmaxMaverick]

At this point, I wouldn't think pump. Injectors, FPR, fuel restriction, fuel supply leak (air), electrical harness (chafing, rodent attack, etc.), poor connection, low voltage, etc. (not in any specific order). With a scanner (Tech II, Predator), you can track fuel pressure and regulator activity, desired vs. actual. If the voltage and pressures are correct, it isn't the pump or FPR.