93 Grand Cherokee Shaking & Shuddering

SpankN, your problem is typical of a fuel deliver or metering problem caused by insufficient fuel delivery or a vacuum leak. If I blew that much black crud out of the line filter, I’d be concerened about the sock filter on the end of the fuel pickup tube in the tank. It may be a good idea to look further, as well as to test the fuel pump.

Vacuum lines do get old an crack. And leak. Bought by the foot, the rubber line is dirt cheap. I’d sugtgest buying some and replacing the lines…ONE BY ONE to be sure you route them correctly and don’t leave any off. They’re all pushin’ 20 years old.

An erratic ignition pulse can also act like a vacuum leak. Can you tell us a bit about the maintenance history? When was the last time you changed the basics, the ignition components and the filters other than the fuel filter?

NanHam, you have an entirely different problem. You have a cylinder or more not firing, or perhaps even an injector not closing. Another much lower probability possibility is a fuel pressure regulator not working, allowing too much squirt…but I consider that a very low probability cause. You have raw vaporized gas blowing up everywhere. I’d start by checking the ignition of each cylinder. Until you get all cylinders firing reliably, you’ll not make any progress.

Let’s try not to get these two problems mixed up. Perhaps a new thread would have been a better approach.