I was gifted a 98 V70 three years ago. I replaced the timing belt the first year and have had to replace a wheel and I just spent $1200 fixing the AC. So in all I've prob spent over $3000 on the car total. I don't use it every day but I love having it to haul gear and go places on the weekends. This past weekend I drove it 2 hours upstate with no issues but on the return trip, in the last 30 minutes or so the engine started to feel like it was loosing power and the vehicle felt like it was shaking a little. There was a plastic burning smell too. This condition seemed to coincide with going under a quarter tank of gas. We only use mid-premium gas because a mechanic told us that the engine will stay a lot cleaner and that everything will just run better. I've noticed the car always seems a lot happier with a full tank. Would going below 1/4 tank all of a sudden drop power in an old car like this. I'm dreading the idea that I need to do another major repair because as I said before I don't necessarily use the car too much and don't know if its worth it to keep sinking money into it. Any ideas???

 

Using mid-range fuel in a car designed for 87 octane is simply a waste of money. Your mechanic is wrong.

Going below 1/4 tank doesn't seem to make sense with smells coming through the AC system. However, the shaking could be a misfire. Those cars still have ignition wires if I recall and by now, a good set of spark plugs, wires, cap and rotor are in order. The parts are inexpensive.

 

 

A misfire will cause the catalytic converter to load up and smell bad. I recommend the ignition repairs that I recommended. You can find what you need online, good quality, good prices.

 

Is the check engine light on at all? If so, get the codes read and report back, and we can go from there, otherwise like Tony said, start with a decent tune up: air filter, fuel filter, new plugs, new plug wires, new distributor cap and rotor.

 

A simple misfire on an extended trip would generate extreme heat in the catalytic converter. It does seem like you'd get a check engine light on that.