S-10 2.8 TBI runs rough midway through warmup

[Vbb199]

I'd probably start with the CTS on this one.

 

[squaredeal91]

I'd probably start with the CTS on this one.

Yep

 

[gmbellew]

you can measure the resistance across the sensor and compare it to the table to see if the sensor is correct.

 

[squaredeal91]

you can measure the resistance across the sensor and compare it to the table to see if the sensor is correct.

This is cool!
Do you know what other years it covers? I think they used the same coolant temp sensor for many years.

 

[gmbellew]

This is cool!
Do you know what other years it covers? I think they used the same coolant temp sensor for many years.

it will be in the emissions and drivability manual for your year. I pulled that one from 1991. I have a 1990 and keep the manuals downloaded to my phone for easy reference when I have an issue. all the manuals are in the reference library. a great resource.

 

[Blackbeard44]

awesome thanks for all of the info, I am definatley gonna try the IAC reset and test the CTS tomorrow, didnt have time to mess with the truck today, we got pounded with snow pretty good lastnight, I was out plowing with my squarebody all day, I should have a 1/2 day tomorrow available to mess with it and will report back

 

[Blackbeard44]

didnt have the time to tinker with it today, but I was able to get plates and tabs for it, so now my motivation to fix it and drive it has increased, only have 1 job for tomorrow and I'm off until monday, I'm hoping to have it sorted out this weekend

 

[Blackbeard44]

well I underestimated the weather guessers, I figured it wasnt gonna be so damn cold, I havent touched the truck in a few days now, its gonna have to wait for warmer weather

 

[Maknwine]

My 87 S10 2.8 with a 4sp trans acted like that one time and it ended up being a vacuum line. IIRC, there was one that came to a T junction and ran down behind the engine and by the transmission. Also had one rot off that went to the canister. Replaced the CTS another time and that is probably it like others have said.
Has the EGR been proven to be functional and clean.

 

[Blackbeard44]

havent taken a look at EGR, and i havent messed with it for a week, there is alot of good advice I have not followed up on

 

[Blackbeard44]

drove the truck today to get some fuel 15 miles or so, when I got back I performed the IAC reset and the truck idles lower now and is alot smoother, I did forget to ohm the coolant temp sensor, but tomorrow before I start it up I will do that

 

[Blackbeard44]

33° outside temp, coolant temp sensor reads 8,980 ohms

 

[squaredeal91]

33° outside temp, coolant temp sensor reads 8,980 ohms

That means it's shot according to that chart. It thinks it's cold AF lol

 

[gmbellew]

That means it's shot according to that chart. It thinks it's cold AF lol

looks right to me? both Celsius and Fahrenheit are shown in the table...

 

[squaredeal91]

looks right to me? both Celsius and Fahrenheit are shown in the table...

math was always my worse subject lol. Now I see it's right on. Somehow I added a digit in my head.