I have a 1992 Honda Accord with a rebuilt transmission from reliable mechanics I've used for ten years. Long story short.. I have a slow oil leak & coolant/anti-freeze leak I check every other day & replace as necessary. I recently realized I left oil cap off on engine & drove about 40 miles round trip. (I didn't know I left off cap until I got home.) With lid off, while accelerating my engine began to sputter. It comes & goes & usually starts after about 5 minutes of being fired up & moving. It smoothed out as I accelerate higher. So, once I hit 40 mph for example, if I stop @ red light, it runs fairly smooth up to 40 mph, then starts to sputter when I try to surpass the highest speed I've previously reached. (41mph in this example). There are no crazy smells, just some burnt oil from where lid was off. My friend who works on cars for fun says I got air in the engine & eventually it will work itself out. Its been a week. What's your opinion? Should I rush to mechanic? Be patient?
Hello. There are a lot of possible causes of this on your vehicle. If this occurred right after the oil cap was left off then it is possible that the engine oil level was low and caused some damage or the leaks that you have may have caused some issues with shorting or misfires. I would usually start by doing a cylinder balance test. This would let me know where the issue might be. I would then do a compression test to see if it is an internal engine failure. I would suspect an issue with a failed spark plug or wire, but it may be a valve problem. If you want to have this rough running checked, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the engine is sputtering] https://www.yourmechanic.com/services/engine-is-sputtering-inspection
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