why is my 97 toyota camry sucking gas?

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Old 31 Mar 2014, 11:54 pm   #1 (permalink)
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Default why is my 97 toyota camry sucking gas?

It has all the basic done on it. New plugs and wires,oil change but still sucking gas
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Old 01 Apr 2014, 12:09 am   #2 (permalink)
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"Sucking gas" ...by this you mean what? Poor gas mileage? As in how poor?

"It has all the basic done on it." which means exactly what?

This car has about 250K plus on the odometer if it has the normal annual mileage (15,000/year). Eventually engines do wear out. Things like rings, valves and valve seats wear. These items, when worn out, reduce compression and overall efficiency of the engine. The only way to know the internal health of your engine is with a compression test and running a vacuum gauge. If the engine has reached the end of its service life (I.E. it needs to be rebuilt) then doing the "basic stuff" isn't going to help.

Less drastic items to consider are:

A plugged catalytic converter.

Dirty fuel filter.

Broken/leaking vacuum lines.

Dirty/plugged injectors.

O2 sensors well past service life.

EGR valve leaking/stuck open and past service life.

Throttle position sensor (TPS) worn past service life.

Inlet Air Temp (IAT) sensor dirty

Manifold Absolute Pressure (MAP or MAF) sensor gone bad.

When you're talking a high mileage vehicle like yours (and I am assuming it is a normal mileage vehicle as you give no info on this) there are a lot of items that could contribute to your (I'm assuming) poor gas mileage. I have no idea how well ...or not ...you've taken care of this vehicle over its lifetime. The items I've listed are normal wear and replacement components that can have subtle or drastic effects on your mileage. O2 sensors generally have a 60-70K mile service life; if yours are original they are toast. Ditto the EGR valve; if it is original it's long past it's service life. A malfunctioning EGR valve can allow exhaust gas to constantly recirculate back into the intake track instead of only when it is required; this situation reduces the efficiency of the engine.

If this were my car I would replace the O2 sensors, swap in a new EGR valve, install a new catalytic converter, replace the fuel filter, replace *all* the vacuum lines, swap in a new TPS and MAP/MAF sensor and clean the IAT sensor.

But before doing all that I would run a compression test and run the engine with a vacuum gauge hooked to it. "Old Skool" gauges but they will tell you a lot about the internal health of the engine. Bottom line: if the internal health of the engine is bad, no amount of external band-aids are going to help bring your mileage back.
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Old 01 Apr 2014, 12:40 am   #3 (permalink)
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not a lot to add to that. very comprehensive.

raised eye brows on this though,

"If this were my car I would replace the O2 sensors, swap in a new EGR valve, install a new catalytic converter, replace the fuel filter, replace *all* the vacuum lines, swap in a new TPS and MAP/MAF sensor and clean the IAT sensor."

never ever replace parts with out testing first. that gets very pricey real fast. all the components mentioned have testing procedures. they can be tested, cleaned, or adjusted. even cataverters can be tested. but it's likely not a cat. not w/o a CEL/MIL lite lit and an o2 code of some sort.


it's possible that the issue maybe an accumulation of things. that's is more than one (usually minor) issue cuminating in the mpg issue.

i would add, check air filter, and change oil iffin it's time. and check the pcv system.

you're likely not going to get much info by reading the plugs. the high energy ignition system tends to burn everything even under some adverse conditions. besides, likely it would have tossed an o2 sensor code iffin the plugs were wet from fuel.

if you need testing info/procedures, you can go here,


purdy much all components listed above will be covered under "electronic engine controls" or "emmissions controls" in the left pane.

that's a free online manual for your vehicle. sign up is free. enter vehicle info and go to "repair help" tab, then the header i listed. or after sign up, just c/p the link into the address bar.

again, it's free!
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