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misfire


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Guest
Anonymous Poster
mikeyziggy@gmail.com

Jul 14, 2008, 9:45 AM

Post #1 of 6 (2578 views)
post icon misfire Sign In

i got a 94 gmc 1500 with 305 tbi at start up engine runs fine lots of power sounds smooth, once engine reachs operating temp. engine will hestiate under a load "driving" if you dont let off the throttle the engine will then backfire. the plugs, plug wires, and fuel filter are just couple months old. i have checked the timing a couple times timing seems to be right. i cant afford to throw a bunch of parts at this old truck let me know if you can help.


way2old
Veteran / Moderator
way2old profile image

Jul 14, 2008, 5:00 PM

Post #2 of 6 (2572 views)
Re: misfire Sign In

Crawl up under it and remove the connection before the converter. Then drive it. Be careful where you drive it because it will be very loud. Or you can remove the O2 sensors (lots easier) and see it that makes any difference. Sounds like you may have a partially clogged converter.



Being way2old is why I need help from younger minds

(This post was edited by way2old on Jul 14, 2008, 5:01 PM)


Guest
Anonymous Poster

Aug 20, 2008, 10:04 AM

Post #3 of 6 (2541 views)
Re: misfire Sign In

your ect sensor is faulty .located just to the left of the thermostat housing


way2old
Veteran / Moderator
way2old profile image

Aug 20, 2008, 1:13 PM

Post #4 of 6 (2538 views)
Re: misfire Sign In

Hey guest. Are you 100% positive the ECT is the cause? Or you just throwing out some answer? Please give us a little more explination as to why you feel it is the sensor. Thanks.



Being way2old is why I need help from younger minds


Guest
Anonymous Poster

Aug 21, 2008, 1:11 PM

Post #5 of 6 (2535 views)
Re: misfire Sign In

95% positive. if the engine runs good when cold but runs worse the warmer the engine gets the ect is most likely at fault.had the same problem last week on a 90 chevy


way2old
Veteran / Moderator
way2old profile image

Aug 21, 2008, 5:18 PM

Post #6 of 6 (2531 views)
Re: misfire Sign In

Backfire and losing power lead me to believe there may be an exhaust restriction. Bad coolant temp sensor would have to be reading cool all the time. Then the engine would be running so rich it would die out at idle. Even if the coolant temp is bad, the ECM still reads load from MAP and TPS. I too have seen CTS go bad, but I don't necessarily tell them it is bad. I may suggest to test it to see what it is reading. Throwing parts is what the poster said they did not want to do. SO please post the testing procedure for the CTS if you have it. It will help poster either rule it out, or be sure it is the cause. Thanks.



Being way2old is why I need help from younger minds






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