I have a 94 grand cherokee with a V8 engine. I love it and I never ever had a problem with it before. The other day I started it and it was sputting and wanted to shut off. I took it for a small run and when i went to start it a few days later, it would start but wouldn't stay running unless I keep on the gas. It sounds like the gas filter to me but I was also told it could be the alternator. Any ideas would be great. Thanks

 

It may be a coincidence that all this started after the belt tensioner was replaced. Double check all connections at the alternator. I would recommend an AVR test to determine the condition of the battery, starter draw in amps and alternator output. This test is usually under $ 30 and should pinpoint the problem(s) easily. Good Luck.

 

The poor idling problem you mention above may be a dirty throttle body / IAC motor. Clean these out with air intake cleaner and see what happens. Also, the ethanol being added to fuel increases its deterioration so that gasoline is only good for 21 days before it begins to degrade. If you don't drive your Jeep often I would recommend a fuel stabilizer. My favorite is a product from Sea Foam.