My old k-jet 240 has had an intermittent stalling issue for the past few weeks. It's been struggling/stalling at lights when driving hard. Today I went over the vacuum lines again and replaced an injector seat o-ring (with a very audible leak) and now it dies every time I brake to a full stop.

I've already been through the usual k-jet suspects, cleaned the throttle body, etc. without any major changes one way or the other. I was sitting in the car while it was idling in the driveway, thinking about how much I didn't want to to start messing with the spark and timing, when I noticed something a little odd.

I had my foot resting on the brake peddle and realized that my RPMs were surging whenever I took my foot off of it. The harder I press the brake, the greater the surge when I let off. It's about a 500RPM change when I press it really hard.

I plugged the line between the check valve and the intake manifold and the the surging stopped. After reconnecting the hose, I took it for another run around the block. If I brake hard, it dies. If I'm extra gentle with it, it seems alright. So now the question is, could something a simple as a bad check valve really cause the car to stall?

thanks


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1980 244 DL