[gpp]

When I go across bumps ,like speed bumps,the truck acts like it's running out of fuel.it only does it when it rocks back and forth kinda quick like.not very many of these side to side bumps do it but it could get dangerous.only does it from 0 to about 10 mph,like when pulling out on the hi way.the other day it actually kinda backfired and sputtered .this has been going on awhile.so I pulled the fuel tank and it's clean as new money.its a 99 and has only 15000 miles on it so I don't think anything is worn out and it runs as good as ever.
Sooo,any ideas as to what could cause this?didnt know if fuel inertia switch could cause it but it's never actually tripped.

 

[Throttle Jockey]

Check the cheap and easy first. When is the last time the fuel filter was replaced?

 

[ty.thompson1981]

Also check all ur connections. My old 98 cobra used to do that. Ran great until I hit a bump and it would shutter and sputter for a bit. Crawled under and noticed the crank sensor plug wasn't snapped all the way on. The little lock clip on the sensor plug broke off. I zip tied the connector to the sensor plug and it was good as new.

 

[gpp]

Oh yea,fuel filter was first thing.after I took the tank out checked every hose and wire for rub spots and loose connections.getting 12.5 volts to pump,sock was clean,tank was clean ,hoses were fine,all the easy stuff first.i don't think the inertia switch is doing it but I'm going to try one.bad thing is I can go to one spot and it does it every time so at least I will know when it's fixed.

 

[Throttle Jockey]

Before replacing the inertia switch I'd troubleshoot the inertia switch relay by swapping it out with one of the other relays that are the same (such as the fuel pump high/low relay which is right next to it).

 

[gpp]

You know about a year ago I had to replace the fuel pump relay and I haven't ever had to replace a relay before .i will check this out tomorrow.