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Discussion Starter · #1 ·
Ok I have read all the posts on rough idling and am still unable to find the cause of this problem. The problem is that my Supra either idles too low, too high or it just jumps up & down like crazy.

Here is what I've done so far:

New spark plugs, new fuel filter, cleaned throttle body, cleaned idle air controller, new idle air controller.

None of this has made the slightest bit of difference and I'm starting to get really frustrated! Oh my Supra is a 93 NA. Please help me :(
 
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Discussion Starter · #2 ·
I had the same problem on my 240. Have u checked for vacuume leaks? It could be a vacuume leak or you might need new fuel injectors? My problem was a vacuume leak.
 
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Discussion Starter · #4 ·
Have checked for vacuum leaks & its not that, not sure about the injectors though but that will be the next thing to get checked out.

What is MAF?
 

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blur2ed.com
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Mass Air Flow sensor...it is the electrical unit right before the air filter itself...if not plugged in will idle all off and normally cut off (essp if OBDII.)
 

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sounds like what happended to me when I gutted my MAF and took out the honeycomb, if you've done that or removed the MAF, you will get an irregular idle.(let me guess, auto?)
also you can try running an FPR that might help.
 

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blur2ed said:
Mass Air Flow sensor...it is the electrical unit right before the air filter itself...if not plugged in will idle all off and normally cut off (essp if OBDII.)
his cars a 93.5 (OBD1)
 
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Discussion Starter · #8 ·
justins_supra said:
sounds like what happended to me when I gutted my MAF and took out the honeycomb, if you've done that or removed the MAF, you will get an irregular idle.(let me guess, auto?)
also you can try running an FPR that might help.

The MAF is connected, haven't gutted it, or even touched it for that matter. But the car was doing this when I bought it from the dealer a few months ago so who knows what's been done to it. I didn't really worry about it because I figured it was a minor issue. Not auto - 5sp manual. What is an FPR?

I'm also thinking of replacing the O2 sensor...
 

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I put up BS Flags
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A FPR is a Fuel Pressure Regulater it basically ummm regulates the pressure of the fuel :) . Any idea if the timing is ok? If you turn your crank to TDC "Top Dead Center" aka the white mark is at the 0 on the Crank Pulley, and then notice and make sure that on the cam gears they have two little notches pointing a TDC aka "12oclock" so your Crank and your Cam gears should all be at TDC or "12 oclock" now check and make sure you distributor is lined up correctly by removing it and making sure the little white mark on it is at the very top or pointing up toward you when you replace it. If you take the distributor cap off then the rotor should be facing towards #1. This will check your timing if you are having an issue with timing.

Hope this helps and good luck,
 

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I rock like CRACK
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Start the car and tap the maf housing, see what it does. I had to replace mine some time ago, car ran like crap for a while until I accidentally bumped the maf, car just cut off. I could duplicate it every time, just start the car and tap the maf and it would cut right off.
 

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Make sure that you check everywhere for vacuum leaks. My car was leaking from the back side of the throttle body where it attaches to the intake manifold. Just get a can of engine starter, and spray a little bit on all of the connections and if your idle increases then that is where that your vacuum leak is. Almost guarenteed that it is going to be a vacuum leak.

Jason
 
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