Starved or Flooded?

[Marcus Merritt]

1994 F150; automatic; 4.9L; 148k miles.... couple of weeks ago poured a can of Seafoam in my front tank (the only one whose pump works) as I have had good results with using this product in other vehicles. Ran the truck and refilled gas tank couple of times since the SF dose. Was going up the expressway last week and had severe hesitation or bogging down when going up hills and even on reasonably level road. Very little going down hills. Could pull off the road, kill the engine and re-crank after maybe 15 seconds and it would do just fine for a couple miles then would begin to hesitate again. I figured the Sea Foam had probably loosened some gunk in the tank and plugged up the fuel filter. So had a new one installed. Truck ran fine for maybe 25 miles on the highway. Got to my destination and parked. Came back out after about 3 hours and cranked it up and, on the way home, hesitation started again. Would clogged injectors cause this problem? I can't figure out if it's getting flooded or starved of fuel. Any solution come to mind beyond having the injectors cleaned? Thanks.

 

[fatherdoug]

I think there is also a strainer that is integral to the fuel pump.

 

[Fellro]

There are little filter screens at the injectors as well. Sounds like you had a bunch of crud that needed dissolved, and the bigger chunks broke loose. Probably going to have to do the Sea Foam treatment again, maybe a few times to get it to clear. The fact that it does fine for a bit then goes back to the trouble indicates to me it isn't clogged, but that they fall out of the way when sitting. I have had fuel filters do this as well. It may even be bad enough that you may have to do the filter again.

 

[smokey]

I had a fuel pump do this also.When it was cold it worked fine but after a few miles it would start causing lose of power issues.
I would test the fuel pressure at idle and under load while it is acting up to rule out the pump.

 

[dustybumpers]

Could be particles floating in the tank too. as you go along, they fill the strainer. Once you stop, they relax and fall off, and back into the fuel tank.
Try siphoning out some gas, and see what it looks like.

Check also for water content in the fuel. could be a lot of water in the tank.
When you siphon out the fuel, the water will settle to the bottom of the bucket.

 

[Fellro]

Sea Foam also helps remove water...