I have put the upper intake gaskets on the vehicle and it start and run a lot better but the 2 lean codes keep coming back. I have made sure the air filter box is sealed around the maf. I can't find any vacuum leaks. I sprayed starting fluid with a scanner connected to watch the fuel trims. The previous owner was trying to fight this and replaced the maf and iac. I found that somebody has done the lower intake and used a lot of silicone on the end seals. That is why I only did the upper gaskets which were bad. The truck idles rough at idle and sputters when cold. Also I hear a loud whistle at part throttle from under the hood. At first I thought a cracked upper intake but starting fluid doesn't effect idle when sprayed anywhere. Recently going up hills the a/c vents change to defroster so I know something is leaking vacuum but where? This is driving me nuts and inspection is due soon. I also checked the maf and out tested good but I unplugged it while running and the idle did not change. When I plugged it in it started having a very erratic idle for a few seconds. Is this odd?

 

I forgot the exact vacuum reading but it was around 22 in.

 

Time to connect a smoke machine and inject @2-3psi, wait and the smoke(leak) will be evident.... Philip

 

I thought of that before. Now I'm making a smoke device. Hope it works.

 

How do you make your own smoke device? and where do you hook it up at? Thanks.

 

I googled it and it's pretty easy. I'm using a small metal container with a lid. I put an air hose fitting on the side and a hose barb on top. I'm going to use dry ice with water to put into it. If I put about 5psi of shop air and hook up the hose barb to the brake booster hose to the intake it should blow the smoke into the intake with the motor off.

 

Not sure if dry ice will work, I tried several methods a couple of yrs ago before settling on mineral oil and a glow plug, I inject the smoke @2psi... Philip

 

it should work since that's what the smoke machines at concerts and such use. If it doesn't I'm going the glow plug route.