I know this is a problem with the v8's not to sure about the 6 banger though. Look at the pcv hose, behind the throttle body, you probobaly have a vaccum leak there, the fix is easy, either get a piece of hose to replace it or go to the dealer and buy a new pcv tube.

 

i just replaced the PCV valve and fuel filter. im willing to bet its a gasket leak issue, and when I get around to doing it im going to replace all the vac lines i can

 

if im looking at this correctly, my metal intake manifold does not have the isolator bolts like the plastic upper intake, correct? all i see for my engine is one gasket set, while a guy who did a write-up had to get two or three gaskets and some bolts for his plastic intake

 

BUMP

I took the upper intake manifold off and found out the pax side IMRC arm was not connected to the IMRCs. The little plastic retaining clip that hold the arm to the bushing is gone. So I went and hooked that back up and now I'm waiting on my new gasket to arrive. I'm not sure how all this equates to unmetered air flow past the engine, but I hope this some how fixes it

 

bumpitdy dumptdity.

nothing helped. still burning a ****-ton of gas. idling ~1,100 rpm now. stock tune. fuel filter changed. no codes.

 

Try using a (unlit) propane torch to look for vacuum leaks.

 

Damn...still chasing this issue...only thing I can think of now is a MAF issue, but I think you already tried that...maybe get a MAF from the junkyard and drive with that to see if the issue goes away..wish I had more but you've tried just about everything but a new motor.

 

Raptor did you replace the manifold gasket or just the plenum gasket? You are sucking air some place.

How is your brake booster & hose? Might also want to look at the check valve on the booster. Look real close at the vapor management stuff all the way back to the tank.

IDK just throwing stuff out there. The un-lit propane torch is a good way to check things out. Maybe pull the battery and check the vacuum resivour and lines leading to it.

 

plenum gasket. since its bank one and two, im guessing the leak has to be up top before it splits. so im going to go to the JY and see if i cant find a stock 4.2L intake set up. filter all the way to the intake manifold and just swap it. I dunno,. maybe my K&N killed the MAF or ive got a small leak in one of the many gaskets. we'll see

 

I know you have a V6, but has your idle ALWAYS been that high?? Is that YOUR normal idle?? My 5.4L idles at 600-700. I haven't read all the replies, but have you tried resetting your ECM just for kicks and giggles? I hope you figure it out brother---DirtySCREW

 

Idle for my truck is 850. PCM has been reset more times than I can count.

New catalytic converters have arrived. Off to the exhaust shop

 

Idle does seem a tad high for being in gear. Is that the idle in gear or in N. I think my tuner set my idle in N to be about 900 and in gear its 635.

 

i have a stick shift

 

how is the frps (fuel rail pressure sensor) the one in my truck is going out just got the part and im going to get it in there soon
makes the truck run rough and horrible mpg i think i got 12mpg highway last big trip i took (medford to portland and back)

 

put that part on and the truck runs a lot better runs smoother and im getting better mpg