frostyllama

iTrader: (3)

i adjusted the idle on the TB and i had it at about 700 and it after a couple of starts it came down to the picture bellow. occasionally the tach will jump around in about 300-500rpm increments unprovoked, some days it will read 4k @ 65, other days 3.5k. wiring, tach, cas, TB? i don't think it has anything to do with the clutch because i did the full throttle at 40 in fifth test with no slipping (referring to the 3.5k 4k variation.) i'm pretty sure the o-ring on the cas is fried so i'm going to start by replacing it.

i just wanted to know if this was even possible for miata engines to idle stably at this actual rpm, because it definitely wasn't complaining (i increased the idle after i saw this):

GVwannabe

iTrader: (1)

what computer are you using? is the battery and coil good?

frostyllama

iTrader: (3)

computer? i have a stock ecu, i haven't checked the battery or the coil, those are probably good places to start. i plan on upgrading to cops, so that should eliminate the problem if it is coil related. i'll check the battery when i get i chance, but come to think of it those two things make a lot more sense.

MartinezA92

iTrader: (4)

Grounds grounds grounds.
This is a really common problem.

Der_Idiot

iTrader: (2)

Check the ground behind the head under the heater core, and on front of the block by the throttle body.

frostyllama

iTrader: (3)

this makes even more sense. i'll check it out when i get a chance.