5.3 engine running odd...

[70rs]

I have a 2000 Chev truck. auto trans, 4x4. All stock (exc K&N cold air intake tube) 150k miles.
A couple of days ago it started to miss at freeway speeds under light load/cruising. Today it backfired through the intake I think. (sounded just like a carb backfire). The miss goes away (at least I can't feel it) when I speed up quickly.
Can anyone give me an idea where to start looking for a problem? I am new to the whole LS thing. I kind of miss carbs and distributors right now.
Thanks for any help anyone can give!
Eric

[ElkyZO6]

Has it ever had a tune up(plugs,wires,fuel filter)? Is the service engine soon light on?

[70rs]

Hey Elky, Thanks for the reply.
I bought the truck with 96k on it and I have not tuned it up since I've owned it. It has always run great till now. (150k on it now, most of that in the first 14 months of ownership)
The check engine light or the service engine soon notification have not come up yet.
I am changing the plugs and wires this weekend (could very well be the original plugs and wires on it). I will also do the fuel filter now that you mention it.
I'll let you know how it turns out after the tune up. Any idea what a set of stock wires runs?
Thanks again. I really appreciate the input.
Eric

[69Camaro]

Stock wires are pricey, I work for a GM dealer in BC, and we will often offer the customer a choice. Normally we install the Aurora wires because they are good quality and manufactured locally. I have had good luck with the MSD stuff as well.

[70rs]

Thanks for the info 69 Camaro.
I'll look into the MSD wires. I can get them localy. It ran like crap today. Tomorrow is tune up day for sure.

I see in your signature line roadracing motorcycles. I am also a sportbike rider. I grew up in bike dealerships and on bikes, my dad worked in dealers all over washington and ad my brother and I with him in all of them. We got an early start. I would go crazy if I didn't have one to ride. Current ride is a 2006 ZX636. There are alot of great roads down here, if you make it down this way this summer to Pacific let me know, I'll head down and cheer you on!

[69Camaro]

Thanks for the offer.. I too go crazy when I can't ride, but this year due to a career change I will not be racing and my street ride is up for sale... until then I intend to put as many miles on as possible.

[ElkyZO6]

Hope that fixes your problem, also I just thought of at work we've seen some fuel pumps not putting out enough pressures.