Hello all, like the title says, my truck is a 454 that started running terrible yesterday. It stalled, it never stalled on me so I started it up, it started but it was spitting and sputtering pretty bad, kinda randomly, seemed worse the greater the load. It was backfiring as well. I noticed my tach bouncing really badly. It even bounced all the way to 5k and then back to 1k and then 3k during the misfire.
I thought it was an ignition issue as when I got home I put an inline spark tester on cylinder 2 and had no spark.
Since I had in stock a new coil, I installed that and still had no spark.
So I moved the tester to the coil. Nothing. Feeling defeated I cranked it again and it started right up and died around 6 seconds. Started again and I moved it into the garage. Stayed running. I tried wiggling wires to no avail. Scanned codes with my tech2 and had a 16,22,35 and 43.
Had to leave so I shut the truck off. Came back a few hours later and wouldn't start, no spark I assume, as I lost my helper. Unplugged my knock sensor not sure how that system works. Truck started. I shut truck off thinking that doesn't make sense, and hooked knock sensor back up. Truck started, but died. Thought no way unplugged it again and it started, but died. Feel like that was a waste, as I sat in the driver seat after it died, I heard a couple clicking noises followed by my fuel pump kicking on. Thought that was interesting so I tried starting it, and she fired up. And this process just keeps getting repeated. So what do you think the problem is? I know the ecm commands the fuel pump on for 2 seconds during cranking, but why the intermittent loss of power? Sorry for the long post, but I swear I get all the goofy electric issues. Please help and I appreciate any help you guys offer.

 

Bad ignition module or pickup coil in the distributor. Your tach bouncing and the intermittent no-spark are classic symptoms. The ECM codes (especially 16 and 43) also point to this. The module is overheating and failing. Replace the ignition module and pickup coil. Check and clean all grounds while you're in there.

 

Ok I was leaning toward the ICM but figured I'd try the coil since I had it. I ordered both the ICM and pick up coil from AutoZone. But does that sound right then with the fuel pump relay? I tried watching voltage to my fuel pump with my scanner, but it never died while I was watching it.
Maybe I should've mentioned this too but it was already late when I made the post but I cleared codes and the only one that came back is that damn knock sensor code 43. I did put a new pig tail on it a few years back. Maybe I should just replace the knock sensor itself as it is pretty beat up, but still works if I lightly tap the block with a hammer. Not sure what else to check there.
Code 16 my Speedo was working and then quit earlier this year. Trucks a 5 speed so it got put on the back burner. Would be nice if replacing the ICM would bring that back to life.
What other grounds are in the intake? I cleaned the one in the thermostat housing real good a month or so ago when I replaced the thermostat. Which I think needs replaced again as this one seems stuck open.
I should be and to replace these parts tomorrow and post back. Thanks for replying.

 

+1 for ICM, I'm on my 3rd one in my 93. Hope that's the fix for you

 

Ok, so AutoZone ordered the wrong pickup coil, for another 5 bucks I thought I'd be better off getting the delphi brand over duralast. So I ordered the delphi went home and put the duralast ignition control module in. No luck.
Installed the delphi pickup coil with the new duralast ICM, and still no spark. I'm going to try and swap back to my original ICM, maybe try my original coil. Not sure what else it could be. My cap and rotor are pretty bad looking. I replaced them I think 2 years ago but I'm not getting spark out of my coil.
My original pickup coil ohmed at .980 k and the new one was around 1.1k

 

Well swapped back to my original ICM. Still no spark. Tomorrow I'll try and get on the computer and try and find a schematic to follow for diagnostic.
Not sure if they have them for OBD1 like they do for OBD2. But that's more for diagnosing codes.
I'll check back here as well to see if anyone else has any ideas.

 

Fixed!! I either got a bad ICM, maybe a pickup coil, but that already ohmed ok like my original did.
Yesterday I ordered a new distributor off Amazon in case my disassembly of the distributor went south.
Feeling like no chance it would work, plugger the new distributors ICM in and spun the distributor gear by hand the spark tester sparked and my fuel injectors pulsed.
Couldn't believe it as I think this is an aftermarket distributor to start with so the assembly itself was in good shape with no corrosion and not extensive shaft play.... But none the less I'm thrilled it's back on the road. Still need to adjust the timing. I see it to tdc #1 and set the timing mark on the crank to 0. I think I left my timing light at my dad's and I'll set it to I believe 4 btdc. Is that correct? Any improvements going a little more advanced? Thanks to everyone who tried to help

 

Well was great, symptoms are a little different tho. Now it misses under a load, actually have to start off in 1st gear, or have to feather the clutch and give more gas then normal to leave in second (if I'm already rolling. Before issues could do it from a stop pretty normal) and if I was let's say in 4th rolling at 2500rpm if I push the throttle down, it will start running terrible, missing, jerking until I ease back into that sweet spot with the throttle. My new codes are 35 and 43. I still get 16 occasionally as my Speedo doesn't work all the time. But Speedo was like this for awhile, so being a 5 speed I don't think that is any of my problem. Also code 43 was a frequent flyer off and on while I had this truck. So I didn't think that's the issue either. I did print out a schematic to follow on testing both codes, but I don't have node lights or any fancier tester then a power probe test light multi meter and tech2. If I stall the truck, because reverse is a little tricky under these issues with having to slip the clutch and give extra gas, it cranks for awhile before starting back up. Last night I put a fuel pump in it because I thought the pump was weak under load. Do you guys think the iac would cause a problem in the mid to upper rpm range? Oh I did have code 42 but I'm not sure if that was just in memory or not. After I previously thought I fixed the problem, I did not reset the engine light, but I did order another ICM and now that code is gone. I do have a used 369 ICM I could try. If you guys still think this sounds ICM related.

 

Remember to use lots of thermal paste for ICM install. Heat kills them

 

Yes I heard that even what comes with them might not be the correct stuff so I bought thermal paste and put on this new one