Here's my problem, truck runs fine then randomly acts like its running on 4 cylinders, I get a check engine light(code 42) It will idle alright but when I step on the gas it falls on its face, stumbles, coughs. Sometimes the issue will go away and I can keep driving, other times Ive had to get a tow. I've done the search on code 42 and gone through a lot of the recommendations, replaced ign module, checked battery connections, tan wire under carpet, plugs/wires, cap/rotor...I'm running out of ideas to check, anybody else had similar issues? Thanks
Code 42 issues..
- Thread starter Gmoney
- Start date
syclone0209
Member
Re: Code 42 issues..
i had the exact same code on my 90 z71. tried all of the ignition components. new dist. cap, rotor. module, coil. and they would just keep the problem away for a week or so. changed ecm and havent had any trouble since. Truck would run fine then it would start stumbling exactly like a bad fuel pump or running out of gas and then just go back normal. sometimes it would be fine for days and other times it would do it right after warming up.
i had the exact same code on my 90 z71. tried all of the ignition components. new dist. cap, rotor. module, coil. and they would just keep the problem away for a week or so. changed ecm and havent had any trouble since. Truck would run fine then it would start stumbling exactly like a bad fuel pump or running out of gas and then just go back normal. sometimes it would be fine for days and other times it would do it right after warming up.
![Quickstop [UK]](/data/avatars/m/5/5165.jpg?1570199786){kind=avatar}
Quickstop [UK]
Combating adversyty.
Re: Code 42 issues..
42 is the disconnected EST right? have you checked the connection at the ECM? wobbly wire would do that.
42 is the disconnected EST right? have you checked the connection at the ECM? wobbly wire would do that.
syclone0209
Member
Re: Code 42 issues..
yes it is the same code as set when you unplug the tan timing wire.
yes it is the same code as set when you unplug the tan timing wire.
Re: Code 42 issues..
Yep sounds like my problem, even replaced fuel pump too. I checked the tan wire and its connected, but maybe in the process of relocating my ecm to the glovebox it forced that wire to come loose a bit...I'll have to check it out
Yep sounds like my problem, even replaced fuel pump too. I checked the tan wire and its connected, but maybe in the process of relocating my ecm to the glovebox it forced that wire to come loose a bit...I'll have to check it out
Matt
Active member
Re: Code 42 issues..
X2 had the exact issue on one of my ty's, light would only come on when i got on it, changed the knock sensor no problems since :tup: also make sure you do not over tighten the new one as this can kill it
X2 had the exact issue on one of my ty's, light would only come on when i got on it, changed the knock sensor no problems since :tup: also make sure you do not over tighten the new one as this can kill it
Re: Code 42 issues..
I had like a temp version of DM for a bit but think its expired...would it hurt to change the knock sensor anyway?
Or, is there a way I can get DM?
Thanks for the help!
I had like a temp version of DM for a bit but think its expired...would it hurt to change the knock sensor anyway?
Or, is there a way I can get DM?
Thanks for the help!
BoostedSUV
Active member
Re: Code 42 issues..
I have very irratic code 42 issues but its mainly when I start the truck. It gives me a hard time starting then it will fire up and throws code 42, I turn it off then back on and trhe code is gone. I too have changed the ign module, cap, rotor, wires, plugs, ECM etc. I also checked all the connections and the wire harness but it still comes up from time to time.
I have very irratic code 42 issues but its mainly when I start the truck. It gives me a hard time starting then it will fire up and throws code 42, I turn it off then back on and trhe code is gone. I too have changed the ign module, cap, rotor, wires, plugs, ECM etc. I also checked all the connections and the wire harness but it still comes up from time to time.
BoostedSUV
Active member
Re: Code 42 issues..
That is correct Dave... I certainly do. I'm starting to think they are related and both issues have been going on for some time but don't necessarily go hand in hand. Just trying to jump on this thread for some more insight since my thread has burned brain cells and has died down.
That is correct Dave... I certainly do. I'm starting to think they are related and both issues have been going on for some time but don't necessarily go hand in hand. Just trying to jump on this thread for some more insight since my thread has burned brain cells and has died down.
nallj92
Active member
Re: Code 42 issues..
i have had imtermittant code 42s come up after the engine rebuild. I just banished the ty to storage until i have more time. Some things im looking into swapping are
knock sensor-New with engine rebuild
ECM-swapped still same problem
memcal- was good before, need to swap out with one from other ty
Distributor, new pick up, cap, and rotor, may replace with reman.
Coil- original
Dist to coil wire- swapped out, worked same
my problems are when the truck is idling the ign referece will drop to 0 then engine will die and check engine will turn on. Happenes randomly, doesnt happen much when cold. Doesnt happen while driving, just idling
Also having a issue with some "false knock" and no retard while hitting engine with a hammer. I have a new knock sensor but might swap it with another again
I do have video of tunerpro when it dies also. doenst show anything significant
i have had imtermittant code 42s come up after the engine rebuild. I just banished the ty to storage until i have more time. Some things im looking into swapping are
knock sensor-New with engine rebuild
ECM-swapped still same problem
memcal- was good before, need to swap out with one from other ty
Distributor, new pick up, cap, and rotor, may replace with reman.
Coil- original
Dist to coil wire- swapped out, worked same
my problems are when the truck is idling the ign referece will drop to 0 then engine will die and check engine will turn on. Happenes randomly, doesnt happen much when cold. Doesnt happen while driving, just idling
Also having a issue with some "false knock" and no retard while hitting engine with a hammer. I have a new knock sensor but might swap it with another again
I do have video of tunerpro when it dies also. doenst show anything significant
BoostedSUV
Active member
Re: Code 42 issues..
Yeah he actually PMed me tonight, I've got him talking in his sleep as well! Haha he mentioned you guys were discussing my issue, I appreciate his determination!
Syclone'D916
Syclone Owner #2414
Re: Code 42 issues..
Now I got the Code 42 Blues. Pretty much the same thing as Gmoney, Drove it today for about 45-50mins a few pullsand a launch, hit some high speeds a few times no problem. Stop to fuel up and wont start. Take a bit till it will then runs rough and bam Code "42". I cleared it by pulling fuse for a few and it will start up fine not to sure if it's the tan wire to the ECM,read i can be that, but i might try to put the ECM it the glovebox(how hard is that to do).
Now I got the Code 42 Blues. Pretty much the same thing as Gmoney, Drove it today for about 45-50mins a few pullsand a launch, hit some high speeds a few times no problem. Stop to fuel up and wont start. Take a bit till it will then runs rough and bam Code "42". I cleared it by pulling fuse for a few and it will start up fine not to sure if it's the tan wire to the ECM,read i can be that, but i might try to put the ECM it the glovebox(how hard is that to do).
Re: Code 42 issues..
Mine will start all the time, but wont run right when its got the "code 42 blues" Then randomly disappears and runs fine. What fuse did you pull? Tonight i'm gonna test out the knock sensor as a few guys on here have replaced that with success. I'll keep ya'll posted with what I find.
Mine will start all the time, but wont run right when its got the "code 42 blues" Then randomly disappears and runs fine. What fuse did you pull? Tonight i'm gonna test out the knock sensor as a few guys on here have replaced that with success. I'll keep ya'll posted with what I find.
Syclone'D916
Syclone Owner #2414
Re: Code 42 issues..
I pulled the ECM B fuse (10amp) and pulled the Neg off too. Still need to put the ECM in glovebox.
I pulled the ECM B fuse (10amp) and pulled the Neg off too. Still need to put the ECM in glovebox.
The Yeti
Got 1000 hp?
Re: Code 42 issues..
Sorry to bump the thread but I have had the code 42 for 2 weeks. I have replaced the stupid stuff like plugs, wires, and ecm and will go for the knock sensor now. Whenever I start it and I get the check engine, it is code 42 so I will turn it off and let it sit for an hour or so after I pull the ecmB fuse and it runs fine after. A temporary fix and very inconvienent but it works right now. I'll update if the knock sensor works for me. I'm getting sick of fuel injected vehicles right now, lol!
Sorry to bump the thread but I have had the code 42 for 2 weeks. I have replaced the stupid stuff like plugs, wires, and ecm and will go for the knock sensor now. Whenever I start it and I get the check engine, it is code 42 so I will turn it off and let it sit for an hour or so after I pull the ecmB fuse and it runs fine after. A temporary fix and very inconvienent but it works right now. I'll update if the knock sensor works for me. I'm getting sick of fuel injected vehicles right now, lol!
The Yeti
Got 1000 hp?
Re: Code 42 issues..
So had the chance to swap out the ignition control module and knock sensor. Figured I'd do both while I had it apart. Truck runs worse now and whenever I clear the code it comes right back after starting it up a few seconds. Idle is crap and whenever you let off the gas while driving it is crap. So far I have swapped in a brand new ECM, cap, rotor, ignition module and knock sensor and am 2 steps forward, 10 steps back now, lol. I have a new coil I may throw on it tomorrow and may buy a new distributor because I really don't know the condition of the one in the truck but now I am running out of options. Checked everything else mentioned in every code 42 thread I could find here.
So had the chance to swap out the ignition control module and knock sensor. Figured I'd do both while I had it apart. Truck runs worse now and whenever I clear the code it comes right back after starting it up a few seconds. Idle is crap and whenever you let off the gas while driving it is crap. So far I have swapped in a brand new ECM, cap, rotor, ignition module and knock sensor and am 2 steps forward, 10 steps back now, lol. I have a new coil I may throw on it tomorrow and may buy a new distributor because I really don't know the condition of the one in the truck but now I am running out of options. Checked everything else mentioned in every code 42 thread I could find here.
The Yeti
Got 1000 hp?
Re: Code 42 issues..
My fix was:
Autozone sold me a DOA ignition control module. Exchanged it for a new one and cleared the 42 code.
Replaced the knock sensor as well. Also DOA. Exchanged it for a new one as well and the truck is back to normal. Figured this was the case after I immediatly got code 43 after the new knock sensor.
So generally on here code 42 tends to be the ignition coil module and 43 almost always is knock sensor. Only torque the knock sensor to about 12 ft/lbs for anyone replacing one that never looked because it will damage the sensor according the older posts. I replaced more than that (cap, rotor, coil, plugs and wires) but it was worth it because I did not know the last time it was tuned up and the cap and rotor were worn.
My fix was:
Autozone sold me a DOA ignition control module. Exchanged it for a new one and cleared the 42 code.
Replaced the knock sensor as well. Also DOA. Exchanged it for a new one as well and the truck is back to normal. Figured this was the case after I immediatly got code 43 after the new knock sensor.
So generally on here code 42 tends to be the ignition coil module and 43 almost always is knock sensor. Only torque the knock sensor to about 12 ft/lbs for anyone replacing one that never looked because it will damage the sensor according the older posts. I replaced more than that (cap, rotor, coil, plugs and wires) but it was worth it because I did not know the last time it was tuned up and the cap and rotor were worn.