Good afternoon

I have a 2005 Chevy Express 2500 with a 4.8L engine and 120k miles on it. Over the last six months, it’* been giving random misfire code/p0300. Since there are a lot of possible causes for this code I am hoping to get some help narrowing down the potential causes.

The check engine light has come on 3-4 times. Sometimes it flashes, sometimes it stays on. The only code it throws is p0300. The only other issue is a very inconsistent ticking/clicking coming from near the engine, more often when the engine is hot. I thought it could be an exhaust leak, but those tick/click more when the engine is cold. It’* not in time with anything. MPG hasn’t changed, I can’t feel a misfire or any rough running.

I am guessing it’* not a sensor, as that ought to throw a more specific code, or at least I’d assume. The spark plugs and wires are newish and looked fine. Also at one point I toot it to a shop and they found histories of misfires on cylinders 1,2,5, and 8.

if anyone has any idea of where to go from here in trying to figure it out from here please let me know.

thank you in advance,
Edward

How many miles have you owned it?

How many miles on the current plugs?

What manufacturer and model are the plugs?

What is the fuel pressure with the ignition on and the engine stopped?

What is the fuel pressure at idle?

How many miles on the fuel pump?

Thanks for replying.

I’ve had it about 40k.

plugs are at about 20-25k, I forget the brand but they were for this engine.

fuel pressure was 55-60 psi with the engine off, I haven’t taken it when running yet.

as far as I know original fuel pump. At least I haven’t changed it

I'd suspect spark plug wires at this stage, but I still wonder about the fuel pressure.

It'* pretty easy to replace spark plug wires on this engine, except for removing the doghouse.

I replaced the plugs and wires, with Acdelco. Drove about an hour and a half, and everything was fine. On the way back though the clicking noise came back but went away somewhere on the drive. Usually once it’* clicking it continues to unless I turn it off. This was the first time it went away while driving.

not sure if that means anything but it’* different.

edward

Sounds like progress!

Can you record the clicking noise and post here?

It has been a bit but I was finally able to get a couple recordings of this noise. The check engine light is not on still. The clicking noise is often associated with bumps in the road, and it most common when doing at least 65mph. It only seems to happen when the engine is warm, and often after it has been started with the engine warm.

thanks for your help

I hear nothing on either.

Same here, I can't detect the tick listening to either recording.

Maybe I hear it at these times:

Van ticking noise.mp3
1.9s
8.5s
20.5s
22.5s
24.0s
24.5s
25.0s

Ticking 2.mp3
0.1s
1.0s
2.1s
2.5s

Is that the sound that we're talking about?

If so, how fast are you driving?

What road are you driving on?

What accessories do you have installed in your van, such as CB radio, GPS, shelves, cages, cabinets, etc.?