petedrex

While pulling a long hill in 3rd at 140kph, 80mph, 4000rpm at about 1/2 throttle, if I accelerate, put my foot into it, it feels as though the ignition cuts out for a split second and then comes back repeatedly. as if an on/off switch is being thrown repeatedly. If I back out of the throttle it will quit this on/off action.
Fuel pump checks out under load, new plugs cap and rotor, premium fuel.
Seems to do this only under sustained heavy load 4000rpm + conditions, does not happen if going through the gears from stop, governor shift to 100mph runs smooth, only on long hard steep pulls.
Runs like a top the rest of the time.
Any help will be greatly appreciated
Pete

LeX2K

A few things that come to mind are a clogged fuel filter, bad ignition coil, or maybe a knock sensor issue. How did you go about checking the fuel pump? Do you have any check engine codes?

Is the engine overheating?

petedrex

fuel pressure checked at fuel in banjo connection with adapter and gauge taped to windshield.
Drove till problem presented itself and found fuel pressure to spec at part throttle and under full throttle operation. Fuel pressure did not waver when experiencing high load, high rpm, full throttle, operation, it feels as though the ignition cuts out for a split second and then returns.
No engine codes set.
New fuel filter, plugs cap, rotor, wires check out good.
Will run a full diagnostic today, road test with snap-on diagnostic hooked up, see if we can find out whats going on.
thanx
Pete