corvairbob

i have this 2000 s10 2.2 auto and maybe 175k it has ran like a top forever. then all of a sudden i have been getting some misfires at cold starts. after it runs for a bit and gets warmed up they go away. there is no codes. and the plugs and wires were new 2 years ago. but i did change the plugs last week and for a few cold starts in the drive it did good. then yesterday it started and ran good but as i sat in the drive getting ready to pull out it started to mis again but by the time i got down to the corner stop it seemed to go away.

i guess i can start changing parts but here is some live data from before i did the plugs. and a photo of the old plugs #1 being on the left. here is the live data i got from a harbor freight scanner the other day

this is what i got engine cold no start yet overnight soak
ect 66 deg it was 67 deg outside
iat 68 deg it was 68 outside so at cold that seem close and under the hood with sun on the hood may have raised it 1 deg
long tft -7.8
map 14.4 psi
spark adv 3.0g what ever g means
02b1s1 0.445 v
02b1s2 0.000 v
remember this was a cold soaked readings and not started yet

then i did a short drive about 1/2 mile in freeze frame and got these.
iat 69 deg
ect 75 deg but it was more i think the trigger happen early it was set to manual trigger
long term -7.8 %
short term 0.0 %
map 7.3 psi
02b1s1 .880 v
02b1s2 .030 v

then i did live data engine running again in the drive
ect 185 deg
iat 73 deg is was 67 deg outside
it ran good this time idle cold and down the road normal accel and hard accel but when i was doing the live data it did start a few misfires

spark adv seems crazy! at idle it was 15 g then when i revved it to any rpm and held it there, it never moved off 15 g but when i let off the gas. the advance would change. this is a first for me i never saw the adv hold stead and then move on decel.

if needed i can hook it up again and get a video if needed but it was stuck at 15 g and during accel it never changed but did change to any number when i let of the gas. i'm not a pro but that makes me think the crank sensor may not be working very well. plus the truck is a gutless wonder at best but i have been told the 2.2 auto is kind of gutless. so any ideas are welcome and to test for. thanks.

corvairbob

ok today i went and did a scan on the 200s and the spark adv moved all over as i figured it would. so i agian scanned the s10 and the spark will move around but then as i start to increase the rpm's it just stays at 15. G what ever G stands for. it had that on the 200s also. so it changes the spark advance on decel but no accel however here is a twist that i did not test for the last time. when i rev the engine and get to about 3500 rpm's all of a sudden the spark advance then starts moving all over the place and the engine rpm's increase lots it will jump to 3500 just like that and when i hold the gas steady the engine surges along with those rpm's jumps. so outside of the TPS might be causing this what else might i look at? the temp gage went up steady both on the gage and the scanner.

i'm leaning on the TPS if it has 4 wires and uses 1 wire to tell the ecu the speed. if not them most likely the ICM but at 200$ i hate to toss one in just to find it was a 10$ sensor? so any ideas

here is a dropbox video of the scanner running.

Dropbox

www.dropbox.com
this video was not reving over 2500 rpm i hope i got them correct. thanks

Dropbox

corvairbob

ok i just decided to get a new map and tps sensor and see if they may be the issue. they are cheap and with over 175k on them they just may be the issue. and it can't hurt. if that fails then the last itei can think of is the icm i found a cheap one on rock auto but because it is a bear to get to i will hold off to give the other 2 sensors a chance. thanks.