Vac. Line diagrahm for 1989 GMC C1500 SLE w/350cid?

make sure to check for a bad tbi gasket as well and make sure map sensorline is in god condition and not soft.

So, there's no 2nd vacumn line on the solonoid....it's a vent, right?
I'll have to look up the map sensor to see what it looks like on this critter.
Thanks, I've replaced the entire throttle body with a remanuf. One & all it's attached components, I've got a new EGR valve & PVC valve.
Had this problem ~2yr ago, & a new throttle position sensor took care of it. But ~ 6mos later it started the same thing again. I changed it out but nothing changed.....so, I eventually just changed the entire TB out. But nothing changed. Limited to ~ one hour a day, it's really starting to P-ss me off...ha!
Again thanks, the 2nd nipple is just a vent & attaches to nothing. Don't have to worry about it anymore.
Rocky J

Ok, I checked the map sensor. I replaced it when I replaced the TB position sensor the 1st time. But, it's worth rechecking!

the vacuum line not the sensor, if the line is old and soft it will suck together so the map can't work right.

Ok,
I'm going to just purchase all new vac. Lines...1/8-1/4 & 3/8" & just replace them all. Their all probably the original lines! It's not like the lines cost the same as Gold! I know the EGR to EGR solonoid line just crumbled.....brittle as H-LL.
If, after that, I'm still having the same problem...I'll update you & see where to go from there.
I really appreciate this. I just don't have the energy to just jump in with both feet & spend an entire day checking every Lil thing like I did before.
Rocky J

one other thing if you didn't change teh gasket under the bi they had a bad habit of blowing andcausing a vacuum leak. then if all esle fails check yoru fuel pressure should be 9-11 psi.

Ok...again thanks, I'll check it.

Update:
I've replaced the Throttle Body before our last talk. Today I replaced the EGR, EGR solonoid, spark control module, pcv valve, all vacumn lines, even the one to the Vac. Canister & it still runs alright for several seconds then Boggs down like its cold or running out of gas. Paddle the throttle a little & it'll catch up & run OK again for several seconds then Boggs down again. It finally tried to idle but it'd start to bogg down & like a governor kicking in, it idle up & run Ok for several seconds again then bogg down again....like it running out of gas or al older carburetor type engine that's cold & the choke isn't working very well.
Outside of fuel pump & fuel filter problems, I'm at a loss. I've got a code reader coming Tuesday PM & hopefully it'll show me something.
In your last note, you said to check the gaskets under the bi ? That's the injectors on top of the throttle body...right. Or did I misunderstand? It's a new "refurbished" TB, but I've had brand new parts that were defective...especially starters in the 70's. Am I correct about the bi? I haven't checked those. I thoughtid double check on what you meant.
Any ideas?
I'll let ya know what the code reader tells me Tues. or Wed. I spent 2.5hrs under the hood today & I'm feeling it. Funny thing is, the EGR was very easy to replace, even though the 2 nuts were a Lil awkward to get to. 20mins & I was done with that part.

the tbi gasket is UNDER the tbi unit.you should have replaced it when you replaced the tbi unit. Also check your fuel pressure i asked you to do that the last post.

OK..I understand now. It came thru as bi, not tbi. I put a new gasket under the TBI when I replaced it. There were several to choose from in the set. One was approx. 1/4" thick & black...the others were thin like the original. The thin one was the one I used. But I'll check it again after I check the fuel pressure. I just forgot about the fuel pressure. All the chemo messes with a guys memory recall. I'll blame it on it anyway. It stormed for 3 days here before I got back to it today.
Again thanks

Hey there got same problem. i got 89 gmc replaced throttle sensors put her in shop tried everything think it a vacuum problem ??

check for a blown gasket under the tbi unit.