Power Brake Booster Problems
 

Hi, I have a 1995 200sx 1.6 l with unknown mileage. I guess it prob has around 225K on it.

Last week it started throwing a OBD2 code of P0170 constantly and had a erratic idle. I did find that the power break booster vacuum hose was leaky near the intake manifold connection. When I touched it with my finger the engine would rev up so I swapped it and all the tubing out all the way to the brake booster with one from my 1996 parts car. (The parts car one looks in much better condition.) The erratic high idle problems have seemed to clear up but I am still noticing that the power brakes often will go hard after the second or third partial depression of the pedal even WITH the engine running. Like when driving in a parking lot maneuvering for a place to park or coming to a stop at a stop sign and letting off the brake a moment to move forward a little to see traffic and trying to stop again. Idle speed hovers around 650 RPMs. Oh, and that code P0170 is still popping up after a few drive cycles. I tried cleaning the MAS and replaced the O ring on the distributor that was leaking oil too.

Guess my question is . . . does the brake issue sound like a power brake vacuum booster issue or should I be looking elsewhere for maybe another vacuum leak . . . or possibly the idle needs to be set higher? I have read someplace these cars with automatics should idle around 800 RPM.

Also, I do have the booster/master cylinder from the 96 parts car's so I could swap them out. While they look like they would be 100% interchangeable it is interesting that the actually vacuum canister on the 96 is about twice as deep as the 95's.

Any help with this would be appreciated :)

Thanks,
Pete