Revelation Z28

iTrader: (10)

i checked all over for vacuum leaks but none came up. whenever i sit and idle when warm or semi warm i get a surge from 1000rpm idle to 1400rpm then either back down to 1000 or it does it back to back. i cleaned my IAC motor still has a little carbon on it but im thinking i need to replace it.

anyone have any other ideas?

juicedimpss

if you made no recent mods,id say its still a dirty iac. have you also tried to clean the little maf wires?

Revelation Z28

iTrader: (10)

maf wires to the maf? well i ran it on speed density map un plugged and it still did it.

would the IAC make it surge above 2000rpm? i think it may be plug wires but who knows.

juicedimpss

actually i was talking about the little tiny sensor wirs inside the maf,but if you are on a s/d tune,it wont matter.
as for surging above 2k,it does that sitting still at idle?

Revelation Z28

iTrader: (10)

sitting still at normal temp itll surge up to about 1500rpm for 1 second and drop back down or repeat it 2 or 3 times in a row.

im thinking ICM now. elec ignition.

itll surge holding the gas steady above 2000rpm. itll also give me a hesitation/misfire while cruising in 2nd or 3rd around 3000rpm.

juicedimpss

cold startup is good?if it has to crank a while it may be a bad fuel pump causing a lean surge
if it is misfiring,id look at the opti plugs.make sure they are not corroded.

Revelation Z28

iTrader: (10)

cranks great.

it has the power it should all the way to 5500rpm. it spins 2nd like all hell. its just a little hickup. between 2000 and 3500rpm. not all the time its more random.

Revelation Z28

iTrader: (10)

it doesnt do this all the time, its periodical

juicedimpss

do you have access to a datalog? it might help to see what the iac is doing.

Revelation Z28

iTrader: (10)

yea ill try to see if i can use it. i checked a little earlier and my ignition coil is loose on its platform or holder or whatever it is. i can move it when wiggling the coil to opti wire.

Revelation Z28

iTrader: (10)

ok today i held the car at 3000rpm and saw the tach jump 200rpm every few seconds. and a popping in the exhaust when it surged. im thinking ICM now and plug wires.

it didnt do anything on idle today until i beat on the car to get the seafoam out of the engine. i unplugged the IAC and it ran great except a few bounces up to 1100rpm.

just for the hell of it and well money's sake, who thinks its the opti?

juicedimpss

check the connector in the top of the opti.
look for blue/green growing in the pins.

Revelation Z28

iTrader: (10)

the car is on its rag i think. LT1 PMS. i tapped the ICM on idle and i get no more missfiring at 3k. the idle is doing good since i unplugged the IAC and ran it then let it sit overnight unplugged.

ill check the connector

Revelation Z28

iTrader: (10)

bump*

found the boot going from the opti to the ignition coil torn 1/4" on the coil boot.

its arching out onto the block i bet. and im replacing the IAC valve. i did a resistance test on it and it came out less than 40 ohms. normal is 40-80 ohms.