Possible Emission system? Help!
 

Hey everyone, i'm new on here and I'm in desperate need of some advice. I haven't found any mechanics down here that seem to know anything about it so I'm kinda stuck. I have an 88 Pickup sr5 that i've done more work too than I care to list. But now ive been having an issue while I run errands. I can shut it off and start it right back up all day long, but when i let it sit for a bit while im inside it wont start back up. All it will do is crank. So i wait for a few mintues (last time 20 min) and it will fire right up. While running it also has a eratic idle. So i'm kind of leaning towards a emission system problem but I don't really know what it could be. Its hard to test because sometimes it will start and sometimes it wont.

And ideas? Id really appreciate any help that I can get. Thanks guys.

Any CEL codes? Can you describe the idle problem more? When you have the starting issue, check for spark and fuel.

Theres no codes tripped besides the Knock Sensor (52). I've been working on that but i'll save that problem for another thread. While cold, the idle is at around 900 or so. During operating temperture, it drops down to the spec 750. But when i'm coming to a stop and push the clutch, it drops to about 500 and sometimes goes up to 750 but sometimes doesn't. I've checked for air leaks in the system and I've visually inspected all the vacuum hoses and proper routing. And sometimes when it doesn't start as quick as it should, I push the trottle a bit and sometimes that will help start it. So that made me think of a fuel problem but the kicker is that it doesn't not start all of the time. I also have a new fuel pump and filter.

well if you open the throtle blades on an EFI motor all you are doing is letting more air in...and if this helps while trying to start your troublesome motor i would lean towards a cold start injector possibly dumping too much fuel into the cylinders....or some leaky injector seals would do it i think...good luck

Try putting a jumper in the fuel pump test plug and see if that helps. what that will do is cause the fuel pump to come on as soon as you turn the key on, see if that helps.