2000 silverado service engine light

[upnorth]

The truck is a 2000 silverado 2500, 6.0l, 130,000 miles. I am getting a service engine light when I am at cruising speed over 55 MPH, It doesn't come on until I am over 55 mph and it goes off as soon as it gets below 50 mph. Takes about 2 minutes of driving over 55 when I first start out, but after that as soon as I reach something over 55 it comes on. If I accelerate fairly hard it goes off til I level off again. No symptoms that I can detect, runs smooth at all speeds, plenty of power and idles fine.

Anyone got any idea of what I am looking at?

[Scott K]

The truck is just telling you not to drive over the speed limit

[Shack]

I would say it could be anything from a TQ issue to an emissions issue.

I have not seen this/or recall it in the past with other makes. Could be anything.

I would have a code scan done to see what is found.

[upnorth]

The truck is just telling you not to drive over the speed limit

Good one

[upnorth]

I would say it could be anything from a TQ issue to an emissions issue.

I have not seen this/or recall it in the past with other makes. Could be anything.

I would have a code scan done to see what is found.

I kinda figured I was going to have to have it scanned, just thought by chance I could avoid it.

[Scott K]

Sorry I am not a Chevy guy, so I was hoping someone else would have your answer, because that was the best one I had . I would pull codes on it and go from there, atleast we would have a direction to go in.

[Jeremy airjer W]

Anyone got any idea of what I am looking at?

A 2000 silverado 2500, 6.0l, 130,000 miles on the rack with a scan tool attached!

There are literally thousands of possibilities that can turn the check engine light on. The first step is to identify the code and then the fun begins! What happens if you set the cruise at 45 for the same amount of time it takes for the light to come on at 55?

[Shack]

Quote:

Originally Posted By: upnorth

Quote:

Anyone got any idea of what I am looking at?

A 2000 silverado 2500, 6.0l, 130,000 miles on the rack with a scan tool attached!

That did make me laugh

[Jeremy airjer W]

Sorry upnorth, I'm in one of those sarcastic moods today for some reason?

[upnorth]

Sorry upnorth, I'm in one of those sarcastic moods today for some reason?

No worries....I have not lost my sense of humor

It stays off as long as I am under 55 MPH. Doesn't matter how far or long I drive it.

[Jeremy airjer W]

Thats weird! Let us know what code(s) come up!!

[upnorth]

I may not be able to have it checked for a bit, but when I get something I will post what I get.

And if I am doing over 55 mph and slow down to under 50 mph it goes off.

[Shack]

I would say if you have no running concerns, you should be fine to wait awhile before having the codes read and a repair made.

[upnorth]

OK...thanks for the replies guys!!

[upnorth]

Just had it checked and the error is P0300 on cylinder 6, according to what I was told it is a random miss. Before someone suggests plugs and wires, I already tried that last week.

I had it scanned at Auto Value and the guy who scanned it said since I already changed wires it could be a sticky injector. Does that sound valid?

I am running some seafoam through it now, yes I realize that is a long shot but it sounds easier than cleaning or changing an injector.

[PierBridge]

Well you should have did a cap and rotor along with the plugs and wires.

My truck did this and it was the Cap!

[upnorth]

I don't think it has a cap on and rotor on that motor. I can't find any reference to a distributor cap and I pretty sure the coil pack don't use a cap and rotor. But good idea though.

[Macgyver55]

The 6.0 motor does not use a distributor cap. It has individual coils mounted above the valve covers and a short plug wire to each cylinder. Same set up as the 5.3!

[Jeremy airjer W]

Upnorth, Why not swap the #6 coil with an odd number coil (1,3,5,7) to see if the misfire follows the coil?

[upnorth]

Upnorth, Why not swap the #6 coil with an odd number coil (1,3,5,7) to see if the misfire follows the coil?

I will give that a try.

[upnorth]

Still there. I am trying to eliminate the easy stuff and I am trying to change the fuel filter and of course the dang lines are stuck good. I have been spraying penetrating oil, tapping the nut and trying to loosen it for a couple hours and getting absolutely nowhere except close to stripping the nut

Anyone have a surefire tip to get those things loose?

I remember the days when fuel filter was under the hood away from all that fricken corrosion, what were they thinking to moving back by the tank