Bought this one 1000 miles ago. Was getting 22per gal. then it stated droping. Replaced plugs (OEM ) air filter and oil change.Tire are new also 235 - 75- 15 Radial air pressure on target. Was put on a dyno, the tech was quite impressed, offered to buy the engine. Also I don't use crap gas, not worth it.Most of my driving is hwy. Approx. 60 miles a day. Thinking it may need a new o2 senser ? Anyone out there had this problem and fixed it? Also anyone gotten any real results from a cold air intake and a larger exhust system, (improved gas mileage),was it worth it?
Why do you think it needs a new O2 sensor? Have you checked O2 sensor output?
What is manifold vacuum at idle? Have you checked the intake snorkel between the MAF sensor and the throttle body for cracks?
What is the current odometer reading?
I doubt if a cold air intake will make a measurable difference in fuel mileage, and you should note that most aftermarket "performance" intakes do not filter as efficiently so the improved performance or fuel economy comes at the expense of accelerated engine wear.
Look at the large 'tube' going from the air filter to the intake plenum. Along with poor fuel economy, if there is a crack in this tube the engine iwll also stumble a bit, because the intake is getting more (unfiltered) air than the MAF is telling the ECU.
Best thing is to take it off and look at it. It 'can' be patched with Duct Tape, or a new one can be had for about $130!!!
Thank You It had a stumbling problem before and that got alot better when I changed the plugs.But there is a litttle bit still happening now. Hadn't thought about a crack in the Air horn. I'll check that in the morning.
My '85 Celica had a similar problem. A mechainc friends reached in with his large hands and wrapped them around the inlet tube, and the car smoothed right out! The cracks were all along the bottom where you couldn't see them!
Whoever told you that does not know what they are talking about.
A bad O2 sensor may cause poor fuel economy, but in my opinion, it is foolish to change it without checking it.
I recommend that you invest in an inexpensive volt/ohm meter. You can get one that will check 95% of the electronic components in a modern car for less than $30 at Radio Shack or Sears, and you will have a tool that is useful for checking most electronic components in the car as well as checking household items.
Once you have your volt meter, you can unplug the connector to the O2 sensor and measure voltage between the 2 terminals in the plug attached to the sensor. With the engine idling, you should see DC voltage fluctuating between 60 and 100 times per minute between around 5 volts and 0 volts. If it is not fluctuating or there is no voltage, then you know the sensor is bad and you can change it.
To check for a leak in the air snorkel, start at the air filter housing and visually inspect for cracks or holes in the black plastic tube that comes out of the air filter housing. You may have to loosen some of the clamps that hold the tube in place to check the underside of the tube.
The proper way to check for a vacuum leak is to use a vacuum gauge, but if the engine idles OK and revs up OK when you apply throttle, then you probably do not have a vacuum leak.
The manifold air flow (MAF) sensor tends to get dirty and fouled over time, and cleaning it with rubbing alcohol or carb cleaner and a cotton swab may improve mileage and performance. The MAF sensor is attached tot he air filter housing, between the housing and the air snorkel. If you remove the MAF sensor, gently clean the bare wire that sits in the air flow. The MAF sensor can become fouled from a dirty or poor aftermarket air filter or from crankcase fumes over time. My guess is that a fouled MAF sensor is causing your reduced fuel economy.
I am not the first one to say that increased performance and/or fuel economy from "high performance" air filters comes at the cost on increased engine wear. That fact is common knowledge among people who are actually knowledgeable about engines. So-called high performance air filters improve performance by allowing more air into the engine, and with the improved performance comes improved fuel economy. The only way to allow more air into the engine is to increase the area of the filter media or increase the size of the passages in the filter media. Most high performance filters do both - they give you more paper and they increase the passage size in the paper. Bigger passages means that fine dirt can get through the passages instead of being trapped, and that dirt mixed with the air wears out the engine and eventually ends up in the motor oil, where it is circulated and wears the engine some more. If you were to analyze your motor oil after 5,000 miles with the OEM filter and again after 5,000 miles with the high performance filter, you would find a lot more non-combustion-related dirt with the high performance filter.
Another drawback to some aftermarket high performance air filters is that they use oil to trap dirt to try to gain back some of the dirt-trapping abilities lost from using larger pores, and too much oil will eventually speed up contamination of the manifold air flow sensor, resulting in reduced performance and fuel economy.
In my opinion, the drawbacks from an aftermarket "high performance" air filter outweigh the benefits, which is why you do not seem them as standard equipment on new vehicles.
Thank You It had a stumbling problem before and that got alot better when I changed the plugs.But there is a litttle bit still happening now. Hadn't thought about a crack in the Air horn. I'll check that in the morning.
If you used aftermarket spark plugs, and ignition wires, that could also be a contributor to poor fuel economy.
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