brake booster???

[Blackzenki82]

so, got some weird issues, was told it was my brake booster from a reliable source...

car has a weird idle, SOMETIMES... idles at like 1200rpm, and at it's 900 it wants to wobble and stall...

now, i just noticed today, that when i apply the brake hard, while idling, that the 1200rpm kicks up to 15-1600rpm...

now, i myselt would asume faulty brake booster, but you guys are the GURUS... not me...

also, if it is the brake booster, would the vac issues also be causing a weird idle?

and finally, is there a replacement for the booster, in case mine IS bad? Z23? Q45? or am i pretty much limited to ordering a brand new one?

[bobbo]

I have actually seen that on my best friends build. Chased it for months. A/F ratios were all over the place and changed when brake pedal was depressed giving an inconsistant idle among other problems. Easy way to check is block off the vacuum assist lines going to the booster.

[Marke]

^^^ What he said to diagnose for sure.

[jdm_fantasy]

Ever get this solved? Having the same issue