2003 x type auto. Ok with gentle acceleration, but misses and bucks under full acceleration.Dealer could find nothing so replaced crank angle sensor.No help. Appears to happen when fuel level low (1/4 full or less).Any one had this experience?

 

Hi Mark

Welcome to the forum, maybe when you get a chance put a post in the new members section about the car as well.

Onto your issue. I'm speaking generally here but sounds like one of 2 things. More than likely a vacuum leak, under the hood, on the right as you look in there is a hose from the intake going towards the firewall. Might be under the engine cover that all of us with later models wish we had. look at the hose and see if it's cracked, next the tube off the brake booster to the intake, see if it's cracked. Also listen for a hiss coming from the 2 black round looking things on the right hand side facing you mid point of the motor. There is an o-ring that fails on the older cars especially.

Or it could be the fuel filter. Runs fine with light to normal acceleration but when you stomp on it it might be starving for gas. All of these are pretty simple and inexpensive repairs you can doo yourself. Run some fuel injector cleaner through and make sure you use premium gas.

You didn't mention a check engine light, usually when the car bucks and it is fuel system related it'll throw a code.

 

Thanks for those tips. Will work through and keep you posted!

 

Another olde trick for tracking down vacuum leaks is to get a can of starter fluid and spray it towards the places that might be leaking. If there is a leak the starter fluid will get sucked in and the engine will speed up.

Some tricks are priceless...
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