help! missing & stumble

[gren95atx]

i have a '95 atx. it idles at around 400-500rpm (rough), feels like its not firing on two cyl's. when i accelerate (slowly) up to around 3000rpm or so, it stumbles like its gaining back the lost cyl's.

a little history:
i had a misfire a couple months ago, determined it was a bad wire. replaced wires and got a new plug. previous to this i had gotten a whole new set of plugs when 60k was done. everything back to normal.

a couple weeks later, again, i had a misfire. except it was on two cyl's. i found it to be the dis module. replaced - everything back to normal.

now its been about a month or so, and another ignition problem has popped up. i replaced the o2 sensors (ran AWESOME until now) and changed the oil earlier this week.

i'm going to check the plugs tommorow. anyone got any ideas?

i'm so SICK of these problems i could PUKE. sorry, i'm just really, really frustrated.

thanks for all your help!!

ross

<small>[ September 28, 2002, 12:50 AM: Message edited by: gren95atx ]</small>

 

[Jr's Sho]

It could be a lot of things, I guess your check engine light isn't on? If it is, pull the codes, or better yet, go to shotimes.com and look up how to run the KOER test to possibly set a code and find out if the problem can be determined. Or maybe just leave my advice alone and wait for the sho gurus to reply. Could be many things... or possibly run a search on here under "engine miss" or "stumble". You will find a ton of info on this exact same problem and it's at least somewhere to look until you get some other posts.

 

[gren95atx]

i've gotten no CE light. i will run the codes tommorow /w the cyl balance test, first thing.

i ran a search, and found nothing. i also tried to look for posts on failing coils (its my guess without further investigation), but found nothing usefull.

 

[gren95atx]

wanted to add one more thing. this conditional happened all of a sudden, it was running top-notch before this. it didn't gradually happen. its like something took a dive.

 

[RStalveyARFF]

the cylinder balance test will definitely tell you whether you're running with a full 6 or not, and tell you which cylinders are dead if not. Do you have any oil in the plug wells by any chance?

 

[gren95atx]

i ran the codes. on KOEO i got 217 - coil 3 failure. on KOER i got no codes, and cyl balance e test checked out ok. the problem is intermidint (sp?), and when i ran the balance test the car was running fine. does a code 217 DEFINATELY mean that the coil is bad? what else should i check?

can someone give me a little info on how to fix this (if it is, in fact, coil 3). are all three coils in one component? is it the box that all the plug wires go into? also any part numbers? and best place to get the parts? best brand?

thanks!

<small>[ September 28, 2002, 12:44 PM: Message edited by: gren95atx ]</small>

 

[gren95atx]

i replaced the coil pack. still does same thing.

 

[Jr's Sho]

Hang in there friend, someone will come along with the fix to your problem soon! wink There's a lot of experienced sho mechanics here.

 

[sdpatt]

Check the ground path to the DIS module: ground strap to the upper bolt on the passenger side rear intake bracket, two 12mm bolts holding the intake's crossover tube to the front and rear plenums and the four 5.5mm bolts holding the DIS module to the crossover tube. Also check the metal terminals on the DIS connectors for corrosion and make sure the connectors are tight. Also check the connector at the coil pack.

 

[RI-SHO]

Looks like my SHO isnt the only one with the same symptoms. My SHO also was running good and just of no where it started missing just like yours and even sometimes limiting it self to only 5,000RPM. At first I was told it was my fouled plugs or dirty IAB, I fixed all that with no new results and now it started giving me cylinder 3-4 codes at first it gave me no codes.

With KOEO I have no codes and have replaced CPS, crank sensor, DIS module, coilpack, plug wires, fuel filter, all with no results and now it wont start at all just a slight gurgle.

Does yours give an ocassional pop when it is idling roughly or when running the cylinder balance test? After I finally gave up and took it to a mechanic he told me theres a big chance its my timing belt even though its about year old. I was further reinforced on SHOForum that it could in fact be timing belt no matter how old it is.

If Scott's help doesnt offer posivtive results I would check the timing while at it too.

 

[gren95atx]

scott - thanks for the advice. i will check those items.

i had one question though. when i replaced the DIS about a month ago, the old one had a tacky white substance on the bottom and i put the new one on clean (other than what was left on the intake). is there any purpose to this stuff?

 

[Slo-Sho]

Yes, a very important purpose. This "white substance" dissipates heat.

 

[projectSHO89]

It's called "Heat Sink Compound."

It is used to ensure good transfer of heat from the heat producer, in this case the DIS, to the heat sink, in this case the intake crossover tube. It does not by itself dissipate any heat.

It is avalable at any Radio Shack for certain, probably any auto parts store also.

Use it to avoid thermal failure of the DIS.

Steve
89