'93 K3500, 454 TBI, poor drivability

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Idaho83815

Newbie
Joined
Apr 23, 2024
Messages
19
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Location
Cocolalla
Had it on a scanner today. No issues.
The Temp Sensor was reading about the same as his laser temp gauge, etc... so that is not likely to cause the poor idle at start up.
We went for a drive and the burble, mis, etc at steady cruise felt electrical to him. He suggested trying a new coil, thinking it might be breaking down internally. He does not like the shotgun approach to parts, but said 30+ year old parts being replaced might not be a bad thing.. he said just do them one at a time and use as educated a guess as possible on what to do first.
I will do the coil and see.
He said next he might try a new IAC to address the idle issue if the coil does not help.
I am not unhappy I have done what I have so far... my wife seems a bit curious/concerned though. It plows us in/out in the winter and takes our garbage to the dump every other week. It does not have a monthly payment.
To date refresher for those interested:
Intake gasket set, TBI gasket, new distributor, cap, rotor, plug wires, O2 sensor, Fuel filter, fuel pump assembly (Was low pressure on key only) Code is gone, steady 16 on vacuum gauge, does not seem to be idling high anymore....
Again I have seen improvements and all likely needed those parts to one extent or another... just some fine tuning to go I guess.
 

Idaho83815

Newbie
Joined
Apr 23, 2024
Messages
19
Reaction score
4
Location
Cocolalla
Had it on a scanner today. No issues.
The Temp Sensor was reading about the same as his laser temp gauge, etc... so that is not likely to cause the poor idle at start up.
We went for a drive and the burble, mis, etc at steady cruise felt electrical to him. He suggested trying a new coil, thinking it might be breaking down internally. He does not like the shotgun approach to parts, but said 30+ year old parts being replaced might not be a bad thing.. he said just do them one at a time and use as educated a guess as possible on what to do first.
I will do the coil and see.
He said next he might try a new IAC to address the idle issue if the coil does not help.
I am not unhappy I have done what I have so far... my wife seems a bit curious/concerned though. It plows us in/out in the winter and takes our garbage to the dump every other week. It does not have a monthly payment.
To date refresher for those interested:
Intake gasket set, TBI gasket, new distributor, cap, rotor, plug wires, O2 sensor, Fuel filter, fuel pump assembly (Was low pressure on key only) Code is gone, steady 16 on vacuum gauge, does not seem to be idling high anymore....
Again I have seen improvements and all likely needed those parts to one extent or another... just some fine tuning to go I guess.
Well I got back to the truck... I purchased an ALDL cable from OBD Diagnostics and am playing with Tuner Pro RT. I also rebuilt the TBI yesterday and did what injector cleaning I could do at home. She is running much better. A slight vibration I still feel in the seat of my pants. I'm probably good with what I have unless someone sees something in the attached tuner pro recording. OOOPs well I guess you cannot upload XDL files... but here is a BLM history from a 15 minute drive. Each value is probably 10-15 pts lower thaan my last tuner pro recording befor I rebuilt the TBI
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