When an engine idles lopey, it means that the idle is uneven or “loping.” There are a few different things that can cause an engine to idle lopey, but the most common cause is an issue with the ignition timing. If the ignition timing is off even by a little bit, it can cause the engine to idle lopey. Other possible causes of a lopey idle include a vacuum leak, dirty fuel injectors, or a clogged air filter.
If your car is idling lopey, the first thing you should check is the ignition timing. If it’s off, adjust it according to your car’s specifications. If adjusting the ignition timing doesn’t fix the problem, then you should check for vacuum leaks. A leaking vacuum hose can cause all sorts of problems, including a lopey idle. To check for vacuum leaks, use a spray bottle filled with water and squirt it around all of the suspected leaks while the engine is running. If there’s a leak, you should hear hissing as the water hits it.
Another potential cause of a lopey idle is dirty fuel injectors. Over time, fuel injectors can get clogged with deposits and dirt which can prevent them from spraying fuel evenly into the cylinders. This will lean out the mixture and can cause all sorts of problems, including a lopy idle. The best way to clean fuel injectors is to remove them and soak them in cleaner overnight. However, this isn’t something that most people will feel comfortable doing themselves and so it’s probably best left to a professional mechanic