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Horrible mileage


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In the last few weeks ive been getting horrible mileage.

I filled my truck 2 days ago and have travelled 80KMS, and im at half a tank already.


So far i have double checked the engine side of things.Everything is good, no leaks or anything,engine does no smoke or consume oil.

things ive done.

-New Rotor

-New fuel filter

-Ran some injector cleaner thru the tank.

-New 02 sensor


My truck is low on power.( been getting worse over the last few months)

It has a small exhaust leak.


Im considering removing the catalytic converter.( anyone ever do this?)

Ive ordered a new cap for the distributor.( still waiting)

I will double check the ignition timing.


what do you guys think i should do/look at?

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1) I would check your intake to see if you have a crack(s) in the flexible tube that goes from the air filter to the intake manifold. Also check the lines that feed into this tube. If there is leakage then the engine is pulling in unmeasured air because all this is after the Mass Air Flow sensor. Unmeasured air means air/fuel ration is going to be wrong.


2) If you want to know how it will perform without the catalytic convert (i.e. to check if it is major restriction) then just pull it and everything after it off. It'll be loud but you can do it temporarily to see if it improves operation. These older vehicles only have an O2 sensor before the catalytic converter. (FYI, my catalytic converter is complete eliminated, but I live in Florida where they don't do inspections)

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Well, the fuel has to be going somewhere so either someone is siphoning it out, you have a leak or you are running rich. I'd say you are 'using' fuel roughly double the rate you should.

Where is the exhaust leak? Pre or post O2 sensor? This could be a big player.

Look for intake/vacuum leaks, check MAF and O2 for proper functioning, check exhaust for block/leak, check ECU coolant temp sensor for proper functioning, and do a general tune up(some you have already). The good thing is that most of this stuff is just labor, not throwing parts/$ at it.


How many miles on thy charriot BTW?



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Low on power and high fuel consumption sounds like a plugged catalytic converter. The only other possibility is having a jumped or improperly set timing belt or some timing issue in general.

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Thanks for all the reply's.

It is a V6, no i havent checked the codes yet, but i will.

The exhaust leak is right neat the cat, so its after the 02 sensor.

My truck has 211000 KM's


ill report back after ive had a go with it, im doing the thermostat on saturday

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Well, if you're doing the T-Stat, you're pretty close to the Timing Belt and Water Pump. Doing those both then will cost you about an extra 2-3 hours of work (depending on how experienced you are) and about $75 max. There's several writeups on how to do both of them. I changed my T-belt myself after having the truck for only about 2 days. I feel dumb for not doing the pump so I'm getting that done next time for sure.


I also recommend seafoam... Try running it through the brake booster line. I can help you out with that too if you wish to message me. The exhaust leak by the cat shouldn't be an issue, and like someone said above, if your state doesn't do emissions inspections, then you should be able to cut that off if you choose.


Here's what I'd do:

Check your timing, and possibly replace the timing belt and water pump with the thermostat (because you said you're already doing the t-stat)

Pull a few plugs (not all at once so you don't confuse which one goes where) and check the plugs. If they're gnarly looking, replace them. Get the NGK's.. they're phenomenal. The first 5 are easy to replace... the 6th one is the common bitch everyone hates.

Check your rotor/distributor.

If you replaced your fuel filter, then that doesn't likely need replacing (unless it's faulty). Run the truck and check to make sure the lines are not leaking!

Check your air filter... mine was so dirty that it caused the truck to run so rich that it'd shut off if running on idle. It didn't look too bad but once I took an air compressor to the filter, I saw the dust plume.


I can't think of much else... It's been a long day here at school and it's time for bed. Let us know how you make out with the truck.. my mileage issue was directly related to my rooftop mounted weather station causing too much drag. I'm going to check my mileage on my next trip next weekend.

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A few posts on here made me laugh. non metered air in a leaking intake will actually cause a lean situation. How does the exhaust look/smell? Do you see any black smoke? Normally using that much fuel would be easy to notice from the tailpipe. I've had clogged converters and the mpg didn't suffer as much as the performance over mid rpm range.


Are you sure your fuel gauge is functioning correctly? Fill the tank to the top and refill after a day and measure fuel consumption vs distance. I would check all fuel lines for any possible leaks, also around the injectors.

A MR2 I owned had a failed mass air flow meter, you can actually see the black smoke when reved :36-:38

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Timing belt was done a year or 2 ago.

The plugs also have been done.

Air filter is new, and clean.

IM sure the fuel gauge is working properly.


do you guys know where i can buy a cat delete? Pre made so i can just remove the old and in with the new?

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