I have an 85 suburban that idles extremely low when started after sitting for 3 hours or more. Also, the choke does not kick in. I have set the timing but it jumps out after being set, causes back firing? What could be the problem? Timing Chain, distributor, cap, wires, plugs? Any help would be great!

i would guess if it jumps out of time after being set its eather your not tightening the bolt on distributer or time belt is going, i belive you have a belt on that year, not sure have to look at manual, get back to you later

whether you have single or double roller style its going to be a chain not a belt. i think they have 305 and/or 350 in them

your right back2life didn't mean to insult you it is chain in that engine what i ment was wether it had ether 1 a chain/belt or the gears intermeshed, like 2.8 v6

Come On Now,im Not Insulted At All! We Are All Here To Inform And Be Informed. We All Make Mistakes, I Know I Sure Do!

Does it start & run right after you set the timing? If the timing chain jumps, moving the distributor won't help much. If it acts better after you reset the static timing, I would suspect the distributor. I've seen cases where the distributor shaft twists and distorts (right before it breaks in two) which will screw your timing up.

You should check if the distributer hold down clamp is on correctly. I had a hard time keeping it positioned right when I was re-installing the distributor. Sounds kinda basic but sometimes basics get overlooked.