My mother gave me this car ... it had been sitting for 5 years in her garage. We drained all the old fuel, put new fuel filter (and a bunch of other tune up items too) and it ran great for 400 miles or so. Then it stalled and had to be towed home. It would start but the idle bounced all over, acted like it was going to die, would drive OK for a few seconds then engine would die. Kept doing that. We replaced fuel filter again and it drove for another 400 miles or so. Then, same symptoms. Had it towed again. Replaced fuel filter again thinking that we might need to drop and clean the fuel tank from whatever gunk was inside. But, this time on the new fuel filter, the symptoms are the same.

So, I'm thinking drop the tank and clean everything in sight (on the inside)? What about a throttle body cleaning? Would that help here? Also, maybe the fuel pump relay is on again/off again here and it's not really fuel but electric related?

Thanks for help.

 

Clean the throttle body and check for broken or breaking vacuum hoses.

 

Pull trouble codes. I suspect crank angle sensor.

 

Well, turns out it wasn't the fuel filter at all. We pulled the Air Mass Sensor apart from its hoses and the whole input screen was covered in bits of foam ... at least 1/2" thick. This older car seems to have had some foam rubber noiseproofing on the aircleaner box and it has broken down over the years and accumulated on the screen. Very little air was getting through. Anyway, it runs great again.

 

Yeah, there was a block of foam in the air box.