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EA82 SPFI slugish , bad mileage


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I have that same problem kinda. Gas mileage has never been to good since I started driving. Usually around 20mpg around town (low of 17mpg) and 28-32mpg on the highway (not complaining). I have noticed the same thing you talked about Scott. Starts right up in the cold, idles at like 2000 to get warmed up then drops to 900+or-100rpm. However, when I start down the road, it bogs around 1500 and then again at around 2200ish. I keep my foot steady on the gas, but it is still sluggish in those rpm ranges. After it gets warmed up its great. I am still curious about the MPGs though. Just replaced plugs and changed oil about 300miles ago. I'm thinking disty is getting a little tired?

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if you have a hotwire MAF be very careful, those internal strands going through the air flow will break easily.

 

a good check for older cars is to go over every piece of sensor harness wiring, i've found a few abd spots in wiring this way that caused intermittent issues. with the car running, start at the sensor harness and keep massaging the wire with your fingers/hands as far back as you can go...usually a foot or two of wire. roll, bend, twist the wire through your hands. a bad spot in the wiring will show itself when the engine starts bucking, coughing, shuts off...or sometimes starts running great if it was otherwise rough. replace any wire that causes these symptoms.

 

tune ups are always good too......plugs, wires, cap and rotor are excellent ideas. i chased a rabbit two years ago on my daily driver...couldn't figure out a stumbling problem and bad mileage. felt like i had done a recent tune up. swapped every sensor in the car...finally realized that while i did a tune up a little over a year prior it was probably 40,000+ miles ago eventhough it didn't seem like that long....replaced the plugs and all was good. all that trouble shooting for nothing.

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Temp sensor isnt even used untill the computer goes closed loop. It wont effect cold engine performance.

 

MAF and TPS are good guesses. Simple OHMs resistance tests on them both isa good start. Cleaning the MAF can help a lot; I wouldn't touch the hotwire with ANYthing. There are sensor safe cleaning sprays one can use. Also might do an OHMs resistance test on the injector itself.

 

Sluggish performance can also be a function of the ignition system. If the dizzy isnt advancing fast enough with the demand it will perform poorly. As suggested above; start simple... tune up :)

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whats the proper way to clean the MAF ? , how does it work?
I cleaned mine with CRC Electromotive (electronics friendly cleaner that evaporates without leaving residue).

 

The MAF heats the wires to a specific temperature. The amount of air passing by will require additional voltage to maintain the temperature. This info is passed to the computer where it looks up the voltage and 'sees' the amount of fuel to provide. The heated wire MAF will compensate for humidity. The water vapor in the air cools the wire more thus more voltage to keep warm.

 

Neato stuff. :headbang:

 

EDIT: Corrected some grammer.

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