2000 Legacy Outback Limited 2.5L -- hesitating and surging when HOT
I have a 2000 Legacy Outback Limited with a 2.5L engine. My problem is that it sometimes hesitates when it is HOT, driving slow in traffic, or especially after itís been idling on a hot day. When this happens I loose about 60 to 80% of the power and the car bogs then surges forward while keeping a constant 1/3 throttle. In the mornings or on a cool day the car runs flawlessly. I also noticed that the car pings quite a bit when itís acting up. The car will also idle rough. I had an engine code that indicated that the rear O2 sensor needed to be change. It was replaced and the code went away. The pipe with the two catalytic convertors was changed (aftermarket) about 7 months ago. Has anyone come across this problem?
Is the fuel line near the new exhaust system and are there fewer or no heat shields protecting the fuel lines? The new exhaust system might be heating up the fuel.It might be vapor lock The lean-out condition from vapor lock may explain the pinging too. Check the routing of the lines and the fix might be adding some insulation around the fuel lines. Is it throwing any codes (check engine light) when the problem happens? Good luck