Rough start knocking after sitting

Had a weird occurrence been outta town so my truck has sat about 10 days. Went to start it and it usually takes it a couple of spins (about 3 seconds) when cold to fire. It fired right up after a second the rpms jumped to maybe a grand and it stumbled and a very loud knock came from the driver side. I smelled smoke like burning oil for a minute then it all was normal.
It doesn’t ever smoke or use oil at all. Has pennzoil full synthetic in it. The knock is what really scared me. I know these trucks tick but this was all out say 3 second knock like no oil was in the drive train. Level is full.

 

is it still knocking when start it it after ?

 

No it stopped after a few seconds then slowly got quieter.

 

i shouldn't see nothing to worry about if it isnt knocking. .mostly like because the truck wasnt started up in over a week it was a bit dry inside soon as the oil circulated reached those dry areas it lubbed them up.. happens alot up here in the north east i have 5 to 10 truck parked at my yard at a time for weeks when i starts them they do the same.

 

I had the same thing happen on my 1992 XtraCab, after it had sat undriven for 2 weeks. Turns out I had water in the gas tank, and it got sucked into the pump & filter all at once.

A buddy and I siphoned out almost 2 cups of water, from the 14 gallon tank, that was only ~half full of gas.

After that, I never had a problem leaving it sit for weeks at a time--but I also made sure to keep the gas tank at least 3/4 full.

You should be ok, but keep an ear on it.

 

I’m blaming it on the sitting. It’s usually driven daily. After swapping to the synthetic oil I’ve noticed the tick a little more when it’s first started.

 

Hopefully it wasn't the oil pump struggling...hard to say for sure based on the description. Keep an eye on it and see if it repeats