2004 5.4 EB. Service engine soon light came on. Idle is occasionally a tiny bit rough, but otherwise runs fine and there is no other indication of a problem. Used BlueDriver to check for codes. I received the following:
I cleared all the codes and the SES light went out, but light and codes returned a few days later.
I smoked the vac system using the brake booster hose as the smoke insertion point. Smoke came out of the throttle body, IAC, EGR valve and the two large hoses that connect to the air intake just prior to the throttle body. I pulled the air intake back enough to seal off the the TB and two large hoses, but still had smoke leaking at the IAC and EGR valve. No smoke anywhere else that I could see. All of the little vacuum lines appeared to be intact.
Question - Is it normal for the IAC, EGR valve to leak smoke?
Thinking that maybe there was an intake manifold leak or something like it, I put the intake back on started the engine. While running I sprayed starting fluid around the top of the intake manifold and throttle body. There was no discernable change in RPM.
So, unless my smoke test was done incorrectly, there appears to be no vacuum leaks (smoke test) or intake leaks (starting fluid test).
Were my test methodologies erroneous?
Should I start looking at component failures? i.e. O2 sensor, MAF, etc?
Any thoughts are appreciated. Thank you!
Ken
I cleared all the codes and the SES light went out, but light and codes returned a few days later.
I smoked the vac system using the brake booster hose as the smoke insertion point. Smoke came out of the throttle body, IAC, EGR valve and the two large hoses that connect to the air intake just prior to the throttle body. I pulled the air intake back enough to seal off the the TB and two large hoses, but still had smoke leaking at the IAC and EGR valve. No smoke anywhere else that I could see. All of the little vacuum lines appeared to be intact.
Question - Is it normal for the IAC, EGR valve to leak smoke?
Thinking that maybe there was an intake manifold leak or something like it, I put the intake back on started the engine. While running I sprayed starting fluid around the top of the intake manifold and throttle body. There was no discernable change in RPM.
So, unless my smoke test was done incorrectly, there appears to be no vacuum leaks (smoke test) or intake leaks (starting fluid test).
Were my test methodologies erroneous?
Should I start looking at component failures? i.e. O2 sensor, MAF, etc?
Any thoughts are appreciated. Thank you!
Ken