'93 c1500 map sensor issues

copperheadcreek · April 30, 2014

Hi all, I have a 1993 c1500 5.7 350 with 318k miles on it. It's been idling rough, bucking and occasionally stalling at stops. It's had a new plugs, wires cap and rotor, IAC, egr checked. This morning I unplugged the map sensor and the issue went away 100% and ran like a champ. (Don't want to run it like this because not sure but I think it will cause constant rich conditions?) i haven't found any vacuum leaks. Going to check the vacuum line from the map tonight. Not throwing any codes. This has been an on going issue for a year or so and literally this morning found something that actually effects it! Anyway I'm really not sure the map itself is out. But I'm not sure what else to look at based on map. Any ideas?

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copperheadcreek · April 30, 2014

Update: feeling really incredibly stupid beyond belief over a year of time and effort many parts and dollars spent... Fixed as of now... Vac line from map sensor was knocked lose from the TBI inlet. ::facepalm:: the worst part is I figured it out on the same day I decided to make my first forum post on it. Sheesh

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txab · April 30, 2014

copperheadcreek · April 30, 2014

After driving it this morning it bucks and kinda sputters when engine comes under load from uphill travel... I guess from here I'm going to replace the sensor and see if that works

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copperheadcreek · May 1, 2014

Verified hose is properly hooked to TBI and map made sure the plug was connected, still loping when it comes under load. Think it's the sensor or something else causing it to read inaccurately? I'm stumped but don't really want to replace the sensor is it's not bad. The tach is jumping too not sure what's with that I some they are connected

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copperheadcreek · May 2, 2014

Does anyone by chance know what the pin b is for on the cruise control module wiring harness. Cruise is out and that pin isn't getting any power. Figure I'd check when I get under the hood later

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