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 Engine skip?

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rjathon

rjathon

Posts : 261
Join date : 2014-10-28
Location : Sun City Center, FL

Engine skip? Empty
PostSubject: Engine skip?   Engine skip? Icon_minitimeTue Oct 27, 2020 10:21 pm

My wife’s 1995 pristine RMS stock with 110,000 miles has a slight what appears to be a skip with the engine that is intermittent but frequent. Going down the interstate on cruise control there is a barely noticeable momentary loss of power that lasts less than half a second but happens every 20 seconds or so. Other than that it runs great. It also happens when not using cruise. Any help is appreciated.
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rcktpwrd

rcktpwrd

Posts : 358
Join date : 2019-03-06
Age : 47
Location : Raleigh, NC

Engine skip? Empty
PostSubject: Re: Engine skip?   Engine skip? Icon_minitimeWed Oct 28, 2020 1:49 pm

could be several things... possibly the torque converter locking/unlocking. maybe bad sparkplug(s) or wires or cap and rotor.
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sherlock9c1



Posts : 2333
Join date : 2009-05-28
Location : Huntsville, AL

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PostSubject: Re: Engine skip?   Engine skip? Icon_minitimeWed Oct 28, 2020 7:39 pm

Check the water pump coolant temperature sensor harness connector for corrosion.  That input is (sadly) not filtered for transients, and an occasional corrosion-related open circuit will tell the PCM that the coolant is at -40F, radically changing fuel and spark, and unlocking the torque converter. If you have an [You must be registered and logged in to see this link.], you can use eehack to datalog and watch the inputs for any goofy transients. That's how I found this issue.

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rjathon

rjathon

Posts : 261
Join date : 2014-10-28
Location : Sun City Center, FL

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PostSubject: Re: Engine skip?   Engine skip? Icon_minitimeThu Oct 29, 2020 7:45 am

You guys are wizards! Thank you very much.
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sdowney717



Posts : 111
Join date : 2017-01-01

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PostSubject: Re: Engine skip?   Engine skip? Icon_minitimeThu Oct 29, 2020 7:20 pm

I had the sensor completely suddenly fail once. Car cut out and refused to start, ECM thought it was -40 outside and was flooding the engine. Replaced and  started right up. Might be worth keeping a spare. An ohmmeter test will show its bad.
AND I think you can UNPLUG the sensor and ECM will default to more normal temps and car will run ok again.
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rjathon

rjathon

Posts : 261
Join date : 2014-10-28
Location : Sun City Center, FL

Engine skip? Empty
PostSubject: Bingo   Engine skip? Icon_minitimeSun Nov 01, 2020 10:54 am

sherlock9c1 wrote:
Check the water pump coolant temperature sensor harness connector for corrosion.  That input is (sadly) not filtered for transients, and an occasional corrosion-related open circuit will tell the PCM that the coolant is at -40F, radically changing fuel and spark, and unlocking the torque converter.  If you have an [You must be registered and logged in to see this link.], you can use eehack to datalog and watch the inputs for any goofy transients. That's how I found this issue.

I checked the sensor. It was corroded. I unplugged and plugged it several times and sprayed some Amsoil MP on it and the problem resolved. I got a new one from Rockauto and will install it.

Thank you very much!
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Fix Until Broke



Posts : 162
Join date : 2019-04-05
Location : Southeast Wisconsin

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PostSubject: Re: Engine skip?   Engine skip? Icon_minitimeSun Nov 01, 2020 11:38 am

Many come with a new plug & pigtails too. If you don't replace the plug, be sure to clean the mating plug/terminals very well else the remaining coolant in the plug will give you the same problem again.

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rjathon

rjathon

Posts : 261
Join date : 2014-10-28
Location : Sun City Center, FL

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PostSubject: Re: Engine skip?   Engine skip? Icon_minitimeMon Nov 02, 2020 6:24 pm

I bought the wrong one. Does anyone have a link to the right part on rockauto?

Thanks
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