Hi, i have a 2004 Volvo S40 1.9 turbo with 55k miles. I need help to fix my problem, when i accelerate the car and let off the gas pedal the engine shuts off and the check engine only says missfire on cilinder 1, 2 or any. I changed the spark plugs, coils, wires and fuel filter but keep doing the same thing.
Have you cleaned your MAF sensor and throttle plate lately as well as checked the air filter? Looked for vacuum leaks? Those all can cause misfires and stalling when returning to low engine speeds. Accelerating dumps more gas into the engine than at the closed throttle position, and somewhat counters the effect of unmetered air from a vacuum leak, or a dirty MAF sensor not reading correctly. WOT also increases the engine's sucking power and it can suck more air through a clogged air filter. All that goes away when you take your foot off the gas and the throttle closes.
yes, i cleaned the maf sensor, throttle body and has a new filter
Spray carb cleaner on rubber hoses under the hood and listen for an idle change. Be careful doing this and try to do it when the engine is still warming up to reduce the risk of a flash fire. Carb cleaner isn't as flammable as starter fluid, but there is still fire potential.
Have you run fuel injector cleaner through the tank? Run a tank of V-Power through the engine or PEA containing fuel system cleaner. A fuel injector may be clogged or dirty and not spraying correctly. Engines need oxygen, fuel and spark to run, when there is an issue with one of the three, it will not run properly. A decent scan tool showing fuel trim will tremendously help you out finding the issue.
Did you change the fuel filter? Sounds to me like a fuel pump issue…
my Volvo C30 (2.0 naturally aspirated C30 85k miles) had an issue with stuttering and replacing the fuel filter seems to have helped…
Yes, i changed the fuel filter to