My first post here and I’m looking for answers/insight. Picked up an 89 S10 Blazer 4.3L sport 4x4 last weekend, drove it home 2 1/2 hours fine but started having issues the day after. I noticed that once it’s up to temp it will idle poorly and stall if you don’t heel-toe the gas while in neutral. At first I thought it could be a bad IACV so I replaced that. It idles much better now but it will still stall after it’s at operation temp. Noticed this morning that I coincides with a drop in oil pressure. I’m wondering if this could be a bad oil pump or a loose oil pickup or if this is indicative of worn bearings. I have no check engine light and there’s no knocking or pinging so I don’t have a code to reference or clear mechanical issue to diagnose. I know the previous owner replaced the sending unit recently but claimed the vehicle “never did him wrong” but I assume he was chasing this same issue but didn’t want to disclose it.

I’d really appreciate any theories or possible solutions on where to go

 

Update, I may be super stupid. I don’t think it’s stalling because loss of oil pressure, I think i was misreading the digital dash and it’s the other way around. Feels like it has a misfire at idle though, it doesn’t always shut off at idle, it’s around once every 30 stops or so. Could a stick open egr valve cause this?

 

Can't speak to the details, but it is often a good idea to check for vacuum leaks.

 

That was gonna be my next step after taking a look at the EGR. I know these engines are simple I’m just not familiar with the layout of them as I’m used to working on turbo flat 4’s so I’ll have to pull up some diagrams