tom1025

iTrader: (5)

2000 z28....car is giving me problems with the check engine light coming on and flashing....last weeki had the car put on a scanner and it came up map sensor voltage high....we noticed a vacumn leak in the hose that goes to the throttle body and 2 valve covers with pcv valve....ordered a new hose assembly and installed it but the light was still on.....today i put it on the scanner again and there were no current or stored codes....took it for a ride and the light was flashing on again....put it on the scanner and still no codes...i tried to count the amount of times it flashed and the first time it was 15 flashes then stopped, next time was 60, then only 7.....when the light flashes the car has no power and is sluggish....mechanic and i cant figure it out....car has H/C/I and a tune with LS1edit.....nothing has been changed recently that would have caused the problem

horist

flashing SES means PCM is detecting multiple misfires

check the plug and wires first

tom1025

iTrader: (5)

plugs and wires are good....TR6s and msd wires......both are only 3months old....pulled the plugs out and they looked good...anyone else have any ideas??

mikenews

iTrader: (9)

Flashing ses light means misfire or multiple misfire.....weird you have no stored codes for misfires.

01redws6ta

Can you read individual cylinder missfires on your mechanic's scanner?

tom1025

iTrader: (5)

update....still have the problem but i have more info.....

checked the individual cylinder misfires and found out #2 is the problem....we switched the #1 and 2 coil packs around to see if the misfire switches cylinders....after we did that the misfire went away and the car ran perfect for 5-6 days then the flashing light came back....checked misfires again and it was cylinder #2 again...so it rules out the coil pack...put new stock plugs back in and the wires are new and good....anyone have a clue on this??? thanks for the help

tom1025

iTrader: (5)

bump....someone help so i can drive the car again...i dont drive it cause it runs like **** and sucks down fuel when running like this

01redws6ta

The next thing I would do is a fuel injector balance test. I work at a GM dealer and this can be done with the Tech 2 and a fuel pressure gauge...don't know if other scanners can do this test. You could also check compression and cylinder leakage if nothing shows up in the balance test.

slmdLS1

iTrader: (8)

mine flashes briefly, but no misfire codes since i swapped wires and plugs as well. i had a p0108 MAP code when i first swapped motors, but it went away. Every time i cold start my car it bucks a little, and stutters until 3k rpms or until it warms up to temp. the MAP was the one sensor i should made sure was on good, but i fear its not on right or isnt sealed.

pphilli1

iTrader: (1)

How big is your cam,compression ratio & what is the plug gap
I have a huge cam in my 402 & I went through TR6's which misfired
& autolites-Finally I used TR55 with .043 plug gap & have had no problems.
This is good plug/gap for a cammed motor with high compression

slmdLS1

iTrader: (8)

if you're asking me,

255/266, 11.3:1, TR6's @ .035 gap. Ive replaced all the plugs and wires and that solved my misfire issues. only code i currently have is P0121 (TPS)