power loss on petrol when under load 4.5lt

[billy3752]

petrol/gas 4.5, mostly driven on gas.
when on petrol, bogs down when trying to accelerate, especially when under load.
ie: taking off from lights & put foot down, bogs down until over 2000rpm, then accelerates ok. if foot backed off it will pickup a bit, but not properly until over 2000rpm.

petrol pump has been changed, fuel injector cleaner has been used, it runs really well above 2000rpm.

could it be the fuel pressure regulator?

[YNOT]

Pressure regulators are fairly reliable.
Check all your inlet ducting from the airflow meter to the engine. If any of those are leaking or not correctly fitted (dislodged by an LPG backfire possibly) then it can cause the symptoms you are describing.

Tony

[Yendor]

Could still be a problem with your injectors.

It is pretty common for vehicles that run on gas most of the time for the injectors to clog up.

The only way to clean them properly is to remove them from the vehicle and have them cleaned.

To test the fuel pressure regulator you will need to use a fuel pressure gauge, this will also tell you if the injectors are leaking.

[billy3752]

thanks for the replys, will do as you suggest, get injectors tested & cleaned.

[fixer982]

Hi Billy. AS YNOT says, Number 1 cause I have found was the air flow meter or air leaks. When mine backfired on LPG, it blew a hole in the sacrificial tube covering from air flowq meter to throttle body. If there is any air leaks along there, the petrol side runs really poorly. Check it our first.

[Bob]

My 4.5L had similar problems. When accelerateing it felt as though it was starving for Fuel. Cleaned MAF Sensor and disconnected Battery for 4 Hours. Fixed the Problem.

[billy3752]

all good now, turned out the second hand fuel pump was suffering same fault as the original, not enough pressure. swapped another one into tank and it's running like a charm.
for the record, car has never backfired on gas., - guess I got a good kit.

[fixer982]

Good to hear its sorted. They only backfire when you are slack with the maintenance like I was. Spark plugs apparently need changing during the life of the vehicle. or so they tell me.