I've recently noticed the sound of air hissing on my intake side. I can't recall if this was a normal sound of my engine or not. My vacuum at idle is a rch over 20" (on a calibrated refrigeration gauge) which is pretty good. I've checked all the hoses and vacuum lines and nothing seems amiss. I've also sprayed starting fluid all over each fitting and hose with no noticable results so I may be alright. Recently, I've taken off the throttle body and ISC valve to install RC engineering injectors and I thought the injector/head grommets seemed a little looser than normal on a stock injector (I installed brand new Toyota grommets) but they definitely appeared to have seated correctly. I also sprayed starting fluid down around each injector where it goes into the head with no noticable changes in idle.
My question is: With your engine running, do you hear air flow/hissing sounds around the throttle body/intake manifold area?
My question is: With your engine running, do you hear air flow/hissing sounds around the throttle body/intake manifold area?
. It could very well be a normal noise, but I don't recal ever hearing it on mine, but I wasn't really looking for the noise either. I'll check my supra this weekend for that noise and see if I have it too.