Low/rough idle, intermitent
wd-40 wont cause the motor to rev. use i would use starting fluid, and that would yield the best results that i know of.
maybe chris will chime in here. but for the time being i would use starting fluid.
Most use propane to check for vac leaks but, only at the intake. If and when checking the lines, use a vac pump and pump down a section at a time and note if it's holding vac or not.
Common areas to check first are your brake booster diaphragm. Remove the hose and pump it down. See if it holds. If not, there's your leak. Then, remove the main line coming off the TB and pump vac. If it holds, all lines are fine. If not, proceed to tracing out which one/s are leaking.
In the rear of the manifold, there's a feed that goes down behind the motor that feeds the tranny. Remove this line from the T-fitting and apply vac. Note if it holds or not. If not, there's a hole, leak in that line. It even may be at the tranny. At the time of hitting something in the road, it has been reported to eject the connection off of the vac port on the tranny thus causing a huge vac leak.
There's not too many to go through so, it's not so bad as it may sound initially. Just remove one section at a time and pull vac on it. If none are found to leak, then I would start checking at the intake level. Work from the top down. Start with the Air Intake to IAC, then to the TB gasket then at the ports, at the injector o-rings, check the side gasket areas that mate up to the heads, to finally a blown plenum gasket.
On the IAC, there's a rubber seal that, if it's not seated correctly, it will leak on you creating a loud hiss. Remove it and check for a dimpled rubber o-ring seal. If it's dimpled or crushed, it needs to be replaced. Check to make sure it's not ****-eyed in the TB. This is another area prone to leaks.
Common areas to check first are your brake booster diaphragm. Remove the hose and pump it down. See if it holds. If not, there's your leak. Then, remove the main line coming off the TB and pump vac. If it holds, all lines are fine. If not, proceed to tracing out which one/s are leaking.
In the rear of the manifold, there's a feed that goes down behind the motor that feeds the tranny. Remove this line from the T-fitting and apply vac. Note if it holds or not. If not, there's a hole, leak in that line. It even may be at the tranny. At the time of hitting something in the road, it has been reported to eject the connection off of the vac port on the tranny thus causing a huge vac leak.
There's not too many to go through so, it's not so bad as it may sound initially. Just remove one section at a time and pull vac on it. If none are found to leak, then I would start checking at the intake level. Work from the top down. Start with the Air Intake to IAC, then to the TB gasket then at the ports, at the injector o-rings, check the side gasket areas that mate up to the heads, to finally a blown plenum gasket.
On the IAC, there's a rubber seal that, if it's not seated correctly, it will leak on you creating a loud hiss. Remove it and check for a dimpled rubber o-ring seal. If it's dimpled or crushed, it needs to be replaced. Check to make sure it's not ****-eyed in the TB. This is another area prone to leaks.
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My dads 00' 5.2 5 speed has a idle problem that comes and goes hot or cold. The air cleaner will also become very loud like it is pulling massive amounts of air. Then out of no where it will pick up and idle good and the noise goes away. The plenum has been repaired and the Iac and TPS hane been replaced. Any ideas? The truck has about 130k on it.
