My 1997 GMC Sierra 1500 Fault Code

[Cruisin']

Hi there,
I'm looking for some help and was wondering if anyone has had this issue with their truck?
My service engine prompt on the dash keeps coming on..
Here's a hedzup from my mechanic as to what he has found and done.

So, the truck keeps logging code P1441 EVAP system flow during non purge.

We initially replaced both the vacuum switch and vacuum valve.
We then recently replaced the valve again using the AC Delco part as recommended.
The AC part number is 01997279
I have vacuum tested both new valves when in place and they both leak a very minor amount that I doubt could be measured.

The alarm is reset and of course, the lit message goes out.
After a couple of days, the engine service message lights up again.

Have any of you experienced this and found the answer to what makes this happen?

The truck is regularly serviced and we're hoping there's a simple fix.
I would appreciate the feedback, as at the moment, we're a little perplexed.
Many thanks,
David

[Just call me Sean]

My 99 keeps getting that code and I'll erase it and it comes back in a few days. I don't know what is causing it.

[speedygonzales]

98% of problems with EVAP are old gas caps leaking. 72% are replacing fuel pumps and the seal leaking.

If you haven't replaced your fuel cap in a while, that's a great place to start.

[special-K]

Any luck with it?

[Cruisin']

Originally Posted by special-K

Any luck with it?

Hi, I need to track down a cap. I'm not using the truck at the mo and doing a few hours on a new contract.
I fired the truck up after sitting for 5 days and the service engine prompt didn't light up... Quite strange....
I'll see if I can get a cap next week and give that a go.
It does sound plausible.
Will let you all know as soon as I can.
Cheers.

[Cruisin']

So.....
I've been using the truck intermittently.
The alarm code has gone out.
The gas cap is tight.
It all seems to be OK....
I appreciate the input from members on here.
Cheers.