What should I do next?

simonindagt · Jun 25, 2026

Hello! Recently bought a 2000 mustang gt w 200000 miles and it's been great until the heater hose connection blew out and I needed a new intake manifold. Pretty much everything is stock on it besides BBK exhaust headers and a pop tune. (previous owners work, not mine) I'm running a dorman PI and it's running ok, but now she's revving kind of high at idle (1400) or coming to a stop. I figured it was one of the hoses coming out of the breather to the throttle body so put a new clamp on it. Better, but still doing it. Time for a new throttle body? I was planning on getting it but installation is another thing. It's a very old motor and it's got valve tick, however she rips around great! Torn on building the current or should I just build one on the stand and run this one down?

96blak54 · Jun 25, 2026

A compromised seal at one of the ports could be not seated properly and pinched allowing unmetered air into the system. Same as the upper plenum seal gasket. Maybe a vacuum port not capped or cracked. Its even possible that the intake manifold may have a crack or not assembled correctly.

SnakeBit! · Jun 25, 2026

Mustang5L5 · Jun 25, 2026

Unplug the IAC when it's idling. WHat happens?

simonindagt · Jun 27, 2026

96blak54 said:
A compromised seal at one of the ports could be not seated properly and pinched allowing unmetered air into the system. Same as the upper plenum seal gasket. Maybe a vacuum port not capped or cracked. Its even possible that the intake manifold may have a crack or not assembled correctly.

Will look into that asap, but the intake manifold is good for sure. I got a vacuum line that's whistling a bit, but the intake is aftermarket and idk where I could find another line for it. Ya think a new throttle body n intake would be the move?