- Location
- In a strange land
Without actually looking anything up (so don't take this as authoritative) I think there is one for the crankcase ventilation (one CCV connector goes to the airbox, the other to manifold vacuum), one for HVAC controls, one for the charcoal canister/evap system and the one you have identified for the brake booster.
You could probably cap off the HVAC port for diagnostic purposes. If capping it off solves your problem you can then try to figure out what has happened with your HVAC system. If that is indeed the issue that will be a new one to me.
If your CCV system is anything like mine was you probably need to replace both valve cover grommets (mine were hard as rocks) and get new connectors (boots?, rubber adapters... I don't know what the parts store is likely to call them) and maybe even replace the lines themselves. For diagnostic purposes you could just cap off the vacuum port which corresponds to the valve cover connection and see if that makes an immediate difference.
The evap system may be a complete can of worms. You could have a problem with that all the way at the gas tank (roll over valves, grommets, vacuum hoses, gas cap...). But I would also expect that to throw a code, and it doesn't sound like you have a CEL (Does your CEL work?). Again, you could temporarily cap off that port and see if it makes a difference. Just expect it to throw a code.
I would think if there were a problem with the brake booster port you would know by virtue of a stiff pedal or a loud vacuum leak. One easy detail to check is the booster check valve. If you shut the vehicle down and then try to pry the check valve out of the booster do you get a release of vacuum? Beyond that it is just a matter of the connections and the line between the manifold and the check valve.
Capping off each of those ports individually should tell you if one of them is responsible for the issue.
The gasket for the intake (and exhaust) to head could also be suspect, but again, I would expect there to be codes thrown if that were bad.
You could probably cap off the HVAC port for diagnostic purposes. If capping it off solves your problem you can then try to figure out what has happened with your HVAC system. If that is indeed the issue that will be a new one to me.
If your CCV system is anything like mine was you probably need to replace both valve cover grommets (mine were hard as rocks) and get new connectors (boots?, rubber adapters... I don't know what the parts store is likely to call them) and maybe even replace the lines themselves. For diagnostic purposes you could just cap off the vacuum port which corresponds to the valve cover connection and see if that makes an immediate difference.
The evap system may be a complete can of worms. You could have a problem with that all the way at the gas tank (roll over valves, grommets, vacuum hoses, gas cap...). But I would also expect that to throw a code, and it doesn't sound like you have a CEL (Does your CEL work?). Again, you could temporarily cap off that port and see if it makes a difference. Just expect it to throw a code.
I would think if there were a problem with the brake booster port you would know by virtue of a stiff pedal or a loud vacuum leak. One easy detail to check is the booster check valve. If you shut the vehicle down and then try to pry the check valve out of the booster do you get a release of vacuum? Beyond that it is just a matter of the connections and the line between the manifold and the check valve.
Capping off each of those ports individually should tell you if one of them is responsible for the issue.
The gasket for the intake (and exhaust) to head could also be suspect, but again, I would expect there to be codes thrown if that were bad.
