lack of performance when running on petrol..?

I found that if you don't use petrol much for actual driving (not just for starting) then you can get microscopic particles of dirt that are too small for the filter to remove that sit in the injector and settle. This causes rough running and poor performance.
I cured an old 80 series by running the petrol tank down really low and putting in a strong amount (1 bottle) of injector cleaner in it and running it for a couple of minutes to ensure it got to the motor. Then I left it sitting in the injectors for a couple of weeks then gave it a flooging on petrol for a couple of km. This did the trick and was fine when I sold it 12 mths later.

Give it a try if it doesn't work then it may be beneficial to have the injectors removed and professionally cleaned and flow tested.

Cheers
Dave

PradoMad,

Is you LPG injected?

Altitude kills power.

The higher you go the worse it gets. The air is thinner and you need more air to petrol ratio to get the engine to to produce the power you would normally get.

As to the LPG, I suspect if it is an injected system that the LPG computer is working well, there seems to be a bit more leeway with air mix on LPG.

How old is the petrol in the tank?
Old petrol has poor combustion.
Common problem with dual fuel vehicles.
Running on gas 99.9% of the the time because it's so cheap petrol is not used and thus becomes stale.
Not a good idea to have petrol in your tank that is more than 30-50 days old.
Suggest drain/use petrol and refill with fresh stuff.
Cheers
CraigB

thank you all for your advise; any thought on the AIR FLOW SENSOR might need replacing?
JS

I had a cruiser on dual fuel & thank God I sold it. But having said that I visited an engineer who told me that a dual fuel vehicle should be tuned to run good on gas NOT both & therefore it must be dynotuned which I did. It never ran better but if I ran out of LPG & switched to petrol the motor would "Ping" under load. As per other bits of advice I would never leave Petrol in vehicle for to long and would replace it often. Good luck.

Gidday Pradomad, Just a thought, I had in the past two VS Commodores on duelfuel, in my line of work I do between 60 - 80000 klms per year, so the cars used to run all the time on LPG, except I would start the day doing approx 10 klms on petrol and finish the day the same way, one car did 340000 k trouble free and the other car did 440000 trouble free, except for a new transmission, and both were running well when i sold them.
anyway i am not answering your question, so i will get to it ok. Because 99% of my running was on LPG when i did need to switch to petrol after a long period, my car would lack power, and run a little rough, and all my garage mechanic would do is remove a fuse [ sorry i don't know which one !! ] and then he would just replace the same fuse after a minute or so, and this would reset the computor, and presto the car would run equaly well on lpg or petrol. so maybe you can ask your mechanic to try this first, it may solve the problem, if not, no harm done eh !
Goog Luck and happy travels Rgs dazren.

When you add petrol next time use 98 as it last longer and has injector cleaner in it.
Cheers Pete

HI

I have same vehicle/setup.

Couple suggestions.

Clean the air flow sensor. Buy the rght can of cleaner at repco etc and follow instructions.

Check the air box has not blown in any way from a backfire. Run your hands around the air box or better still just pull it out and flip it over and check it. I have blown mine 3 times before i changed brands of my leads and plugs. Easy fix if its blown, run a soldering iron around and melt/fuse/weld it back together.

WHat leads and plugs do you have? Since i have changed all runs better now.

I had problems with a failed air flow sensor prior to going to LPG. All toyota tests showed that there was nothing wrong with it. Professionally changed and cleaned injectors but no difference. Even were suggestions re bad fuel etc too. It took a mechanic to suggest swapping the air flow sensor with one thats known to be good to check if any difference. Bingo - problem fixed. So new one fitted and no worries since.

Mine is regularly tuned by gas specialist but I also notice that it seems to run brilliant on gas even towing and either ok or good on petrol. I have also noticed a difference depending on where i have bought the petrol from as after its gone and refilled any minor issues have gone. i had more of a problem with leaking petrol from under dis-used filler pipe, but luckily i have now solved that one. good luck with it....

Has it got an equalizer tube in it ?? I imagine it would have if running a snorkel. They are fine with out a snorkel but as soon as a snorkel is installed unless its equalized it will run like a pig. If you run on LPG all the time the injectors will slowly glag up due to lack of use and leaving a residue on them. The LPG on the 3.4 95 series is a venturie system which I found in mine lacked power especially when towing or on sand or needing the extra grunt. The equalizer tube comes out of the air box you should be able to see it. Regards Steve M

wow...thanks everyone for the great feedback. Will get to work now. I have this setup now for about 2 years and I am very happy so far. I have just changed the gas specialist and he actually mentioned that the Prado is one of only a very few models that adapt to the dual setup without any problems whatsoever. Thanks again
JS.