98 Jimmy - Loses Power At Highway Speeds.

[coreybv]

Hello folks,

 

I've got a 98 Jimmy that is having an intermittent problem. Occasionally at highway speeds it will completely lose power, not even being able to maintain the current speed. When this happens, however, it will still idle smoothly. At idle, if you try to rev the engine, it will only get a few hundred rpm above idle, and backfires. Usually, if I just shut it off and let it sit for a few minutes it will be fine again, sometimes for a few miles, sometimes for a few hundred miles. We can drive it around town and never have a problem as long as we keep it below about 50 mph or so.

 

The check engine lite is intermittently on, and there is a code for the mass airflow sensor, however this code has been there for several years, long before this problem started, so I'm unsure if it's related.

 

I also pulled the dipstick and the oil has a strong gasoline smell.

 

Any thoughts? I need to get this on the road quickly (and hopefully cheaply ), since my girlfriend frequently needs to take this out of town and I don't want her getting stranded somewhere. As I said, this problem is very intermittent. Sometimes it will only go a mile or two down the Interstate, but at other times we've made ~300 mile trips with no issue.