hi i need some help here, i have a chance to p/u an 01' blazer with a horrible miss...I've looked it over the trk was just tuned up cap,rotor,wires, and plugs. There was no difference in the way it runs.. U start it up and it just misses badly, then will sometimes die out...and if u drive it it will die when u stop.. Here is what else that i know about it.. the rpms flutter?? when u rev the motor or should i say bounce badly.. It did throw the code for a crank position sensor mechanic supposedely changed it didn't solve the problem.. I've checked for a crossed wire nope...none! it is running extremely rich like it's dumping fuel I wanted to know if it's normal for the ignition control module to get HOT??? i mean really hot when it was running earlier.. I see that the distibutor gear is a problem for some people but was kinda leaning towards a coil and icm??? So please what do u guys think??? I'm not a chevy guy so i really need your help...is there something that i'm overlooking??? Thanks in advance!!!!!!

I forgot to add that i cleaned the throttlebody and the mass airflow sensor

 

If it is running really rich, it could have a fuel leak inside the intake. Also, you may want to test the compression.

Many autoparts stores used to be able to test the ICM & coil, but they seemed to have stopped doing that kind of stuff. It shouldn't be all that hot, but it has a heat shield for a reason.

 

OK cool i'm debating on this still i can get it for super cheap.....guess i need to research some more on this

 

If the current owner will let you... pull the plugs and look at them. If it's running rich then it sounds like a fuel dumping issue to me.
Could be a bad fuel pressure regulator (located at the spider under intake).

 

Well i'm sure she will let me, i did pull the 1cyl. plug and of course it's jet black!!! i did let her know that i'll take it.... gonna be a couple weeks though gotta save up the money! This is good though i'm developing a plan of attack I think i'm first gonna pull the distributor though cause of the fluctuating oil pressure.....hoping that's all the further i have to go!???? I'm hoping the gear is chewed up???

 

Ok update!!!!! So i got trk to my place and pulled the distributor and lone and behold the gear was worn bad!!! I replaced with new distributor and ran better but still running rich which i figured it would. I pulled plugs today and all of them were soaked with gas, and 1 had a cracked insulator, so i got plugs and tested fuel pressure and it was 60psi and as soon as pump shuts off it drops to 54psi.. i had checked the psi at the filter which is new, btw... and i'm getting 58 psi and holding for 10 min it drops to 54... now i figured there must be a problem with the fp regulator, replaced that and now the pressure jumps to 64psi and immediately bleeds right off!anywhere from 40 to 10psi I've checked connections and nothing....i might wanna add that i've pulled all the poppets out and checked them all.....to no avail Could i have a bad fp regulator????? I know i'm missing something here just not sure....i've read the threads that are posted and just am confusing myself here... Can anyone see what i cannot?? I've checked the lines for leaks, only to come up empty handed.

 

Did you replace the upper intake gasket? How does the vacuum connector in the intake look? I just conquered the same problem on an engine change. The $27 upper intake gasket is a silent problem creator. good luck

 

Well i have the intake gaskets, but upper pendlum is still apart. I'm not seeing the intake gasket as the culprit here?? Is there something i missing in what u are saying??? Are u referring to the connection for the brake booster? if so yes, that is fine. Could i have an internal leak in the CPI unit itself??? As i mentioned i replace the FPR and now the pressure bleds right off, anywhere from 20-40 psi? this is what has me stumped... I'm half tempted to find a newer one from a salvage yard! I believe that the pressure to the filter is fine, and it only bled off 4 or 5psi after 10 minutes, so doesn't that mean the problem is further up towards the regulator??? I got a wuestion for someone... can u hear the cpi unit filling with fuel,when the pump runs?? I kinda figured this is normal.

 

there is a fitting that is in the upper intake that the pcv connects. Also it feeds vacuum to the a/c controls. if you have a gasket change it. Trust me, i just went thru all the same issues. I changed all 3 gaskets after i chased the fpr,injectors and plug wire path. It runs like top now. If that is the original gasket, they seem to be a one use item. good luck

 

Ok cool i'll check that..... I still got this thing apart....still trying to figure out if the spider is bad, thinking that there is a intenal leak, since i cannot find one on the outside... I know that there is a leak somewhere, just not sure if it's that or not.