Low idle stall

[INChubbs29]

Hi my name is Aaron, I am brand new to this forum but have read quite a few other pages to accumulate knowledge.
I currently own a 1991 GMC Jimmy SLX model with A.C. and the 350 engine. I have been working on the emissions, overall reliability and function of the truck. I have replaced all the vacuum lines that I know about, new mapsensor, new EGR control solenoid, and cleaned the EGR valve and passage way. It has a new distributor cap and rotor, new spark plugs, and I cleaned and rebuilt the fuel injectors. It has a new fuel pump, and filter. I recently checked the timing on the engine and it appears to be dead on, and the electronic advance working properly. The issue I am experiencing is a low idle stall, especially when I first switch to reverse. I am very uncertain about what could be causing the issue and have made little headway in a diagnosis. I have not yet ruled out other potential vacuum leaks or possible low fuel pressure slash volume. Any help or advice would be very much appreciated.

 

[Bent77]

Hi my name is Aaron, I am brand new to this forum but have read quite a few other pages to accumulate knowledge.
I currently own a 1991 GMC Jimmy SLX model with A.C. and the 350 engine. I have been working on the emissions, overall reliability and function of the truck. I have replaced all the vacuum lines that I know about, new mapsensor, new EGR control solenoid, and cleaned the EGR valve and passage way. It has a new distributor cap and rotor, new spark plugs, and I cleaned and rebuilt the fuel injectors. It has a new fuel pump, and filter. I recently checked the timing on the engine and it appears to be dead on, and the electronic advance working properly. The issue I am experiencing is a low idle stall, especially when I first switch to reverse. I am very uncertain about what could be causing the issue and have made little headway in a diagnosis. I have not yet ruled out other potential vacuum leaks or possible low fuel pressure slash volume. Any help or advice would be very much appreciated.

My first guess would be a dirty IAC

 

[INChubbs29]

My first guess would be a dirty IAC

Ah yes of course, I will definitely check that out and keep posting

 

[bp71k5]

I’d also check the pcv valve. A dirty one was causing mine to do the same.

 

[INChubbs29]

Hey guys so as an update, I cleaned the IAC and it seems to be doing great! On the unlucky side my heater core started puking coolant yesterday so I have that fun chore to fix. On a different topic I was wondering if I could possibly find out more information about my truck, it was made in August so I would assume it has or had a birthday coming up. Seeing as 91 was the last year they made the K5 Jimmy and there were only like 7400 made I was kinda wondering where mine stood in line. How would I go about finding this information?

 

[wheels87k5]

https://www.edmunds.com/driving-tips/making-sense-of-your-vin.html

 

[INChubbs29]

https://www.edmunds.com/driving-tips/making-sense-of-your-vin.html

I have looked into that as well, but unfortunately it only tells me that the last 6 digits are the build sequence numbers. And that "build records, are generally available only to the vehicle's manufacturer and its dealers. Try contacting the manufacturer or dealer directly to see if it will provide them".

 

[INChubbs29]

I have looked into that as well, but unfortunately it only tells me that the last 6 digits are the build sequence numbers. And that "build records, are generally available only to the vehicle's manufacturer and its dealers. Try contacting the manufacturer or dealer directly to see if it will provide them".

Unless the example of the Cadillac given would be the same for my truck? "In the case of our Cadillac ATS, it was the 125,409th car to roll off the assembly line" but that still wouldn't narrow down to much in the case of my truck. Seeing as the blazer was still in production along side the jimmy, and other engine options were still available with the Jimmy as well.