# Coughing under stress and at high RPM



## SoB (Sep 23, 2006)

The truck coughs heavily under load in like 3rd, 4th and 5th gears... if I rev sitting still it's ok, but as soon as there's a load on it... like trying to climb a hill, or in 5th or 4th on the highway, it coughs so bad the whole truck shakes. This can't be good... just got the truck so I'm just looking for ideas atm. I've put some injector cleaner in, and I'm thinking I should change the fuel filter. Truck is an 1987 ext cab.

Richard


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## Ville (Mar 2, 2005)

SoB said:


> The truck coughs heavily under load in like 3rd, 4th and 5th gears... if I rev sitting still it's ok, but as soon as there's a load on it... like trying to climb a hill, or in 5th or 4th on the highway, it coughs so bad the whole truck shakes. This can't be good... just got the truck so I'm just looking for ideas atm. I've put some injector cleaner in, and I'm thinking I should change the fuel filter. Truck is an 1987 ext cab.
> 
> Richard


change it and see what happens, but I doubt it would solve your problem unless the fuel filter is full of dirt. check every rubber hose of your fuel system, maybe some hose is being pressed by something and it doesn't let gas pass as it should. it happened to me once and it was very tricky because I tough I had a carburetor or fuel pump issue, I'm not experienced with FI cars but if you discard every fuel pump. lines and inyectors I would guess it's a bad ecu.


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