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Rough Idle Issues 91 k1500
First I am somewhat of a Noob. I am mechanically inclined, however when it comes to what this or that might be or what causes this or that. Ya im a noob.
And thats why I am here. My issue is that i also have a very rough idle.. truck runs great but at idle it seems like its misfiring, and if im coming to a stop and engage the clutch 30% of the time it dies out. What I have done so far. Cleaned out carborator (if thats not what it is please give me the proper term or name) using carb cleaner did a full tune up: Cap, rotor, plugs, air filter, and plug wires Today i was told to try the o2 sensor. So i went to take off the o2 sensor to bring it with me to auto parts store (so i get the right one) and there wasnt even a wire on it. Now i dont mean to say it was un plugged. I mean some one cut the wire off of the sensor completely. Furthermore the wire is no where to be seen. So i re-ran a new wire from the ecm to a brand new o2 sensor. Still same idle issue. 91 Chevy K1500 5.7 v8 Manual One final note.. There is a tube that runs from the vapor canistor (i think) to a sensor or solenioid.. and out of that it runs to under the carb.. now this sensor or solenoid seems to have had a plug in at one time. but again it has nothing plugged into it at all, nor is there a plug to be seen. Thank you. |
could be MAP sensor... or EGR
Originally Posted by VOLTAGExDT
(Post 181240)
Fi
rst I am somewhat of a Noob. I am mechanically inclined, however when it comes to what this or that might be or what causes this or that. Ya im a noob. And thats why I am here. My issue is that i also have a very rough idle.. truck runs great but at idle it seems like its misfiring, and if im coming to a stop and engage the clutch 30% of the time it dies out. What I have done so far. Cleaned out carborator (if thats not what it is please give me the proper term or name) using carb cleaner did a full tune up: Cap, rotor, plugs, air filter, and plug wires Today i was told to try the o2 sensor. So i went to take off the o2 sensor to bring it with me to auto parts store (so i get the right one) and there wasnt even a wire on it. Now i dont mean to say it was un plugged. I mean some one cut the wire off of the sensor completely. Furthermore the wire is no where to be seen. So i re-ran a new wire from the ecm to a brand new o2 sensor. Still same idle issue. 91 Chevy K1500 5.7 v8 Manual One final note.. There is a tube that runs from the vapor canistor (i think) to a sensor or solenioid.. and out of that it runs to under the carb.. now this sensor or solenoid seems to have had a plug in at one time. but again it has nothing plugged into it at all, nor is there a plug to be seen. Thank you. The fact that it starts, runs, and dies after shifting/driving for a little tells me it's most likely the EGR. It's a round/disc like sensor that opens and closes a rubber diaphragm and when it begins to fail it exhibits the issues you are experiencing. It could also be your MAP sensor as well. Are there any Check Engine Lights that remain on after initial ignition or are flashing when you're driving at all? You could always just try putting a paper clip into your OBD1 port and make sure. Lastly, since it seems like the previous owner liked to cut things off and delete them rather than replace them. Check underneath your truck to see if you still have a catalytic converter. If you don't, it can cause the issues that you're experiencing as well. And, if you do have a catalytic converter, take a rubber mallet and give it a decent smack. And if it hear what sounds like Christmas ornament's breaking/shaking around you may need a new catalytic converter. Also, check your fuses. Vacuum lines and hoses are connected/leaks (if you google 91 gmc wiring diagrams or gmc 1991 sierra repair manual you can find those for free as PDFs I downloaded from 1988-1998 manuals and wiring diagrams). |
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