The other day I was driving on the highway at about 65 mph and upon giving light acceleration, the car bagan to shudder. I immediately let go of the gas and it was fine, did'nt shut off or anything. I tried to accelerate again and it did it again.

I quickly pulled over thinking something may be loose but that wasnt the case. After pulling over, I gave it gas while idling and it revved fine and idled fine. Thereafter it drove fine with no repeats.


It has something to do with the engine but I cannot point it out as there was no check engine light. Is it possible that it may be the fuel filter? The only other symptoms i can think of that may or may not be related are that sometimes the idle acts funny as if it wants to shut off or dips slightly. Sometimes the car also starts up in the morning kind of rough, and shuts off when reversing or beginning to accelerate. Also sometimes, under boost, the car hesitates for a seconds as if it falls flat, and the starts accelerating as if nothing happened. All of these symptoms happen occasionally and not regularlyso its tough for me to diagnose.

The car now has approx 170-180 K miles on it. Within the last year, the folowing things have been replaced:

spark plugs (oem Bosch)
spark plug wires (bougicord)
Distributor cap and rotor (Bosch)
PCV system,
Air Filter,
MAF cleaned with electrical cleaner
Oil changed regularly using Volvo filter and 5w30 castrol syntec oil


Things I have not replaced in regular maintenance:

fuel filter

Like I said, I dont know if the shudder on the highway and other symptoms are related, but I would appreciate the advice. Thanks.

 

It could be starving of fuel at load because of fuel filter. So, I would replace the filter first and then go to next step if required. Check the connector for cam position sensor and for the ignition coil (High Voltage contact and Low Voltage contacts). any corrosion marks or contamination there can produce these symptoms.