Have you tried fabricating a block off plate for the EGR valve out of thin sheetmetal to use as a diagnostic tool? Get two gaskets and sandwich the sheetmetal plate between the two gaskets and the EGR valve and tighten it back down. See how the truck runs then.

It sounds like a sensor issue that is causing the problem.

 

yea it probaly is a sensor but i got a propane torch now and tomorrow im going to see if i can find any vacuum leaks. i ran it about a hundred miles today had a little over half a tank and when i got back had about an 1/8th of a tank left. but it ran fine on the highway and at stops. but when i get out and go in the store then back and start it back up then it will surge and want to die. and will smooth out within a minute. i went to pass somebody on the highway and my engine light came on and went to a autozone and got the code 32. but when i restarted the truck it went away. and drove fine untill idle. and my anti lock light came on also as soon as i parked at autozone. didnt run those codes didnt know how. but went off when restart. anyway i looked under the hood and saw what looked to be oil under the master cylinder. so i rubbed it on my finder and it was just WATER not antifreeze, WATER. and it came from the brake booster vac line.so i unplugged the vac line and no water ran out of it but did look a little wet. i dont know if this is causeing the surging or not. but when i was working on it when pulling the intake manifold i had to stop because of rain. a downpoor. so maby water got into it idk. and i did change the oil after i put it back together. but what weird is that when in park it surges and run rough and when i put it into reverse or drive it will smooth out and run just fine.

 

Man... That is horrible fuel mileage!

 

Check your park/neutral switch on the lower steering column. It can affect the IAC and EGR as it's used in that circuit.

 

The unlit torch idea is awesome never thought of that before. Does your tempeture gauge work ? Are you getting the same codes again ?

 

no codes. but i tried the unlit torch to find vacuum leaks and it didnt notice any change in idle speed. but i might get a vacuum gauge and test it with it. what psi should it read to be ok? and where should i hook it up too? if it tests out ok then i can rule out vacuum and start checkin something else. but for some reason im getting a little water from the brake booster vacuum line and dont know why. its not alot but enough that its wet and dripping onto the steering shaft.

 

havent got around to getting a vacuum gauge 50 bucks to rent. anyway does anybody know why its surging in park or nutral and runs just fine in drive or reverse D 2 1. when it gets warm after about 3-5 minutes it will run just fine in park or nutral. but if i shut it off for about a minute or two it will surge in park and nutral but not in drive or reverse. and after about a minute it will smooth out.

 

Vacuum levels vary vehicle to vehicle. You can diagnose an issue by placing the gauge at various locations in the system and comparing the readings with full manifold vacuum straight off the intake manifold.

Surging at idle is a sign of a vacuum and/or EGR valve leak.

BTW, you can bump your post. A PM is not necessary.

 

bam 999, keep me updated. my 93 blazer is doing the exact same thing. would love to see how yours plays out. my uncle is a mechanic and he told me that i have a vacuum leak and i tried starter fluid spraying it around listening for and idle change and nothing. i also pulled the hose out of the black ball idk what its for but i know the line has plent suction i bew smoke from a cigar into the line from the ball with engine off to see where the smoke came out and it came out through a hose that is capped off at the top of the firewall. but its supposed to let air out. it has vent in the cap i think. and to swartlkk...you have any advise for me? my airconditioning also blows through the floor and the defrost but not through the vents. could this be fixed with the same vaccum leak or do i have a accuator bad somewhere in the dash and wich one would be if its in the dash? thanks for any advise from anyone.

 

if your dash vents are not working and not switching from floor to top then you probally have a vac leak in the dash where the heater controls are. take the heater controls out of the dash and make sure that all the rubber hoses are connected. or start it up and put your ear up to the switches and listen for a hissing/ sucking noise. they might have just popped off. and i totaled that blazer before i could figure out the real problem. but i think when i put in the new intake gaskets the didnt seal right and was letting antifreeze into the cylinder and thats why it was surging when cold but not warm since it was burning it off to quickly to cause problems. are you loosing any antifreeze?