I have some problems with the truck. It has a high mileage of around 300,000. Recently, the engine started chugging. It occurs when the weather is bad. When I drive it at the rainy day, it runs a bit rough. It starts and idles well but after a while the engine starts chugging at low speeds around 25 mph. It lasts very shortly and the trucks runs fine after that. Is this serious? Does this happen because of the moisture?
It is very possible that moisture is getting into the connectors of the engine control module. The connectors should be checked and cleaned if necessary. Di-electric grease can be used to help seal the connectors and keep the moisture out. Fault codes should also be read out of the engine control module to ensure that there are no other failures that could be affecting the drivability of the engine. You may want to enlist the help of a mechanic, such as one from YourMechanic, who has the expertise to prevent moisture ingress, and has the equipment to interrogate fault memories and determine the cause of your engine hesitation.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing