V8 Limited Revs

Hi all

I pulled out to overtake a van yesterday as I acceleated my rangie decided it was going to to its usual kickdown and rev to hell before it change up. However this time when the revs reached about 4500 it seemed like the fuel cut off and the reves dropped back to 3500 and it started to rev again and kept doing this rather than accelerate.

I have just redone the heads on the car and replaced the plugs and leads at the same time.

Rangie idles and runs up to 3500 rpm fine and cruised fine.

Anyone got any suggestions on what could be the problem

NB it is a 4.6 V8 with LPG, problem occurs on both gas and petrol.

A bit more information on this.

The engine seems to loose power under load, took it up one of the local steep hills and it started to stuggle, the engine continued to loose power until I took my foot off the accelerator. the sam thing happens at about 65, the engine starts to struggle and then loose power

Have a look at the MAF sensor. Recent thread on this i think.

wammers said:

Have a look at the MAF sensor. Recent thread on this i think.

Click to expand...

Thanks Wammers. I have tried going for a run with the MAF sensor unplugged and the engine seemed more hesitant and still exhibited the lack of power.

so I don't think the MAF is the problem

I have cleaned the MAF as it was quite sooty and there does seem to be some improvement, but the engine is still loosing power.

Do I need to get my fuel trims reset as well?

I have also put a OBD code reade on (after cleaning the MAF) and had the following codes:-

P0327 - Knock sensor low Bank A
P0332 - Knock sensor low Bank B
P0171 - O2 Sensor Lean Bank A
P0174 - O2 Sensor Lean Bank B

I also had code P1319 & P1816 - not listed

Would these all be symptoms of the MAF being faulty or could I have a fuel pressure problem?

Andy_J said:

I have cleaned the MAF as it was quite sooty and there does seem to be some improvement, but the engine is still loosing power.

Do I need to get my fuel trims reset as well?

I have also put a OBD code reade on (after cleaning the MAF) and had the following codes:-

P0327 - Knock sensor low Bank A
P0332 - Knock sensor low Bank B
P0171 - O2 Sensor Lean Bank A
P0174 - O2 Sensor Lean Bank B

I also had code P1319 & P1816 - not listed

Would these all be symptoms of the MAF being faulty or could I have a fuel pressure problem?

Click to expand...

Hi Andy, I know it's an old thread now butI have the same issues with my 4.6. Did you ever get to the bottom of it? If so, what was the issue?
Cheers, Dave