New problem. Eng missing out. CEL on but gives code 55

[silverkaturbo]

Setup is ka24des14 t28370ccstock mafemance tune

Please bear with me: The car has ran great for the past year and a half when I was running my t25 and sidemount. I recently moved up to the t28 an front mount and for the first couple months all was well.

But one day i was cruising down the highway and out of nowhere i felt the motor kind of miss out and jerk. Then my check engine light came on and it continued missing out and smoking. afrs maxed out at 10. When I got home I checked the ecu and the only code it would give is 55 but the cel stays on.??? I pulled the plugs and they were pretty dark (as usual). I cleaned them popped them back in and check eng light went away and problems were solved for another couple weeks until the exact same thing happened. Ive been going through this cycle for awhile now but occurences keep getting closer together. This last time though i cleaned the plugs like always put them back in and it started missing out a half a mile down the road. I had thought my tune is just rich so it was just fouling plugs now and then but after this one im starting to think its something else. Any ideas?

I wouldn't think the ecu would ust start malfunctioning so suddenly, butthe past couple times though my ecu will not give me codes. The red light just stays on when i try running the diagnostics like I have been.

[baron_harkkonen]

well i don't know what to tell ya, if it clears up after you clean the plugs, try changing the plugs. if the problem still persists check out your cap and rotor. if there is any sign of corrosion, change em out. then start looking at your ignition system as a whole. your coil maybe goin kaputs, could be your ignition control module actin up. check your pick-up coil on the distributor, it could be the distributor goin out. if all these check out ok, or if you've replaced what appeared to be faulty, start looking past that.

every engine needs three basic things to work: fuel/air mixture, compression, and spark. if the plugs appear fouled out, your running rich, get a hotter plug or check for air/vaccum leaks after the throttle body (past all the main sensors).

this is what i've found, importtuner.com/tech/impp_0101_reading_ecu_trouble_codes/index.html

i'll keep checking to see what else i can find. also try callin a nissan service department and see what the service manager has to say.

[silverkaturbo]

I've already replaced cap and rotor, and put new 10mm wires on it. Its wierd though because one night I tried swapping back in my untuned ecu just for kicks to see if it would bring up a code other than the no problems 55 when something is clearly wrong, but it wouldn't. It ran like crap of course but i just had it idle for a few minutes. So I put the other (tuned) ecu back in and the cel was off and it ran perfectly again for like the longest it ever has since the problem started; even without cleaning plugs. But after about 30 miles it happened again. I tried the ecu switcheroo again but had no luck;cel remains on.

The ecu's inability to run diagnostics anymore has me thinkin it must be at fault, but im a little reluctant of going through the hassle of swapping my chip over, especially if it isnt even the problem.

[silverkaturbo]

Well it happened again today. Got about 15 miles this time. Tried running diagnostics again and it worked this time, but its still only giving me 55. Any other suggestions anyone???

[trackslut240]

can be your MAF, i had a similar issue with mine, it would kick cel on while cruising. after about 10-15 miles, so what i would do is just switch off the key at 55mph and switch it back on, will run another 10-15 miles and same routine. swapped the maf and all is well. the trouble with trying to catch such a code is, for u to go into diagnostic mode u have to turn the key off, key off means ecu reset, no more code. this was when i was still na, its actually worse when the ambient temps are low or humid.