# 93 Altima Runs Perfect for 25/30 miles, THEN



## jughead (Mar 5, 2012)

HELP! it runs perfect for a few miles... and then I get a intermittent, rapid pulsating, surging, situation which will not stop until the car cools down (it WAS not hot,  just normal engine temps). Black un-burned fuel out the tailpipe. Car will eventually die at a stop light - but will start right back up. Tach will bounce up and down up to to 800 rpm every second (under throttle). Runs best at about 2300 rpm but can't be driven long (it will drive you nuts). Here's what I have tried: I have a 94 245k on it and the 93 158k that I'm having the problem with. I'm swapping parts from the 94 to the 93' in hopes of finding the EXACT problem with no luck YET. Swapped or bought these items: the fuel rail, regulator and injectors, bought new fuel filter, new plugs and wires, swapped egr and back pressure transducers (I can't figure out how to get the wires off the purge solenoid to swap them). I have replaced the original fuel pump with TWO new "Made in China" units - I'm swapping out the MAF sensors today... I hope I did this right (1st timer)
many THANKS


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## CMax03 (Jan 17, 2009)

bad gas...put some STP gas treatment in your tank and run it down!


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## CMax03 (Jan 17, 2009)

Or get it started and start pulling plugs to locate the dead cylinder! Which is the one that doesn't drop any RPM....troubleshoot if it's spark plug, injector, cylinder sealing, etc


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## smj999smj (Jan 1, 2006)

Sounds like a bad distributor to me... Any oil inside the distributor cap?


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## jughead (Mar 5, 2012)

Thanks Guys, It was the Mass Air Flow Sensor that was causing my problem. I knew there was a reason why I kept that old 94 Altima (kept swapping parts til a found the problem). AMAZING. I could drive it for the 25 miles and it ran perfect BUT when I shut it off, that would apparently heat up the car a "little" bit and active an unknown HEAT type sensor which actives the MAF sensor. Oh, by the way there is a fine wire which wraps around the plugins on the MAF sensor and the purge solenoid plugin. Pry them off carefully with a small straight screw driver and the plugins can be removed.


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