missfire

[pontiac3100]

whats going on.
my 94 pontiac grand am gt 170k miles on her is having a lil' problem.

when the engine is cold (temp on 100*F or lower) she missfires bad...
then once she warms up it goes away.

then when the rpms is 1,200-2000rpms you can hear like some popping noise from the exhaust and the engine shakes a lil' as if there's a missfire.

when your on the highway between 50-60mph/1,200-2,000rpms with the t/c locked if feels as if she miss firing.

i don't know what else to do....someone told me it could very well be the engine.
but it does'nt sound like it and man you when get on her....she responds EACH AND EVERY TIME.

please help me out
thanks

[pontiac3100]

someone??anyone??please??

[IsaacHayes]

Are the plug wires in good shape? Start with all the basics. Spray some water on the plug wires while it's running and see if it starts running rough. If so then time for new wires.

[pontiac3100]

yea the wires are fine.
i went and got the right pcm today.
so now the rpms "missing" range is now in 1,000-1,300rpms.
i was leaning more on the 24x sensor since it seems to be a low rpm thing going on...

[IsaacHayes]

Yeah could be. Ive never had it go out but it does affect low rpm and idle.

[pontiac3100]

hmmm so lets say i remove the harness then it'll revert to limp-mode.....i wonder if it'll get better.
if so DAMN! THATS GONNA BE A PRETTY PENNY!

[IsaacHayes]

24x costs that much? Junk yard for the win!

Not sure if disconnecting will help. It may run worse, or be the same. Not sure if that would tell you either way much. Can you get it scanned somewhere? I hear autozone scanners can only read codes if there is a check engine light it cant read stored codes or anything else...

[pontiac3100]

well...i have a 94 and for some 94/95 gm vehicles.
they're somewhat called "obd1.5"

meaning it has some of the obd2 features but also obtains the obd1.
so i have the obd 1 connector but can't do the pin trick.

but i have no codes.

oh and the price for a 24x sensor cost about $50-70 at napa (don't buy from auto zone).
i mean the labor...and if i do it myself...i dunno.

[pontiac3100]

bump

[pontiac3100]

bump

[pontiac3100]

okay i checked the coils

1/4= 6.3

6/3= 5.9

2/5= 6.0

this was using a dvom in 200k ohm.

the primary was 1.0.

this is when they're warm...i'll update on a cold

[IsaacHayes]

Are the spark plugs old? What kind/brand do you have? Maybe you have bosch or something that tend to not be the accurate heat range.

[pontiac3100]

update when cold (put em in the freezer)
2/5=5.1

6/3=5.1

1/4=5.3

again the primary was the same.

[pontiac3100]

as for the plugs they're rapid fire 6...there a couple months olds. about 30k old....

okay i just checked the fronts.

okay all of em (2,4,6) they had some white stuff on em'
but 4 and 6 looked like they had red stuff on them too....
what the hell is that?

[z34phoenix]

the white means they are runing lean. i liked my rapid fire plugs and i know everyone recomends them, but i went to a colder plug and saw good results... you might benifit from the same.

one heat range colder would be something like the autolite AP104 or APP104 for single or double plat plugs. these are also cheep (ap104's)

my guess on what that red stuff is.... i think it might be the copper coming thru the platinum?

i would also look into a good injector cleaning... maybe even a prof job where they hook the system up to a presurized system to clean them.