Sorry guys, I thought that thing was connected to the ignition harness.

Turns out it was connected to the harness that controls the turn signal/cruise control stuff.

 

That thing in the picture is the rod that works the shift out of park with foot on the brake safety deal for the lack of a better word , this will not affect the ignition switch use with caution if disabled.

 

Drove like a champ all day. Thanks for your help Mayhem.

Got some beer money for you. PM me.

 

Ignition switches are not common as some would have you believe, more often than not it is PMD/FSD , in OBD-I trucks can be OPS related as only single source of power for the lift pump in those, OBD_IIs 96+ have dual power to lift pump but that does not negate bad lift itself or bad gnds.

For benefit of others reading & may not know Gnds on vehicle are more than just the ones on battery connection points, multiple gnds on the PCM controlled trucks, for stalling issues and shutdown randomly the aft rear intake manifold to head stud pass side is VERY IMPORTANT that one goes to the PCM diirty/loose here causes intermittent shutdowns, needs to be super clean test with meter stud to battery neg terminal should be less than 1 ohm resistance

Remember with the "puterized" trucks large draw stuff is 12Vdc smaller stuff like engine sensors and op amps used in the PMD/FSD run on 0-5.0 vdc modulated voltage and poor connection at various gnds corrupt sensors being accurate to the PCM and negatively impacting performance and can also shut you down.

 

I'm late to the party, it's been a while since I've participated this forum or any others for that matter, I read previous posts and wasn't quite sure final outcome here that got you back up and running, was it the ignition switch or the multi-function turn/cruise switch ?

Your truck is OBD-II and has a "smart" PCM and monitors the vac via the baro-sensor on the firewall, just plugging off sensors like you can in OBD-I trucks not going to work for you without coding,

EGR system can be "massaged" into thinking its working if you know what you are doing.

If you have ever taken the upper intake off of the lower intake from a S/L56 engine code (EGRd) there is a 1 time use gasket that seals the center ""EGR tower" in the center of the S lower intake, if that has deteriorated over time or was fully crushed it can allow for full time flow of EGR gasses into the intake poor economy/black smoke.

 

Get rid of the EGR. I just pulled my intake top off last night and was amazed by the gunk. I've had the vacuum line off the EGR and plugged for a while. I thought that would help.

Get an F upper and lower intake and be done

 

Can't do that on OBD-II the puter goes batty when is "sees" missing sensors you can blank off the EGR but PCM unless flashed to not look for the pressure drops on vac system as solenoids actuate and are sensed by firewall baro that stuff has to stay functional.

Tim

 

It was the ignition switch. She hasn't been more reliable since I swapped it out.

Turns out the factory key was worn out, and that was why it was tough to turn. I used the back up key that looks freshly cut and and it turns so easy now.

Didn't think the key would wear out before the ignition lock! Just didn't compute...

 

Ithought people had done it and switched the ECM. Am I wrong on that?

 

You can swap ECMs IF the ECM is from same year and gear ratio etc. setup S to F ECM, if not there is a possibility some of the year to year changes may cause conflict, so if you don't have ability to match vehicle to vehicle other than S or F then you need a reflash, which is what you are going to need anyway if changing to a different turbo as your fueling/boosting/shifting etc. won't be "optimized".

My first "performance" adder was to run a 96F PCM in my 98 S truck which gave more fuel but that was with the GM8 turbo, then I had Heath's 1st performance tune put into it with the GM8, when I did that I had the S stuff "shut off"

I went to the ATT and it worked ok....it went back/forth a few times 5-6, to get a "best" with the ATT I ran that for a number of years,

In July 2013 I finally put in my "project engine" balanced & blueprinted CKO HD block & heads, with the Heath performance cam and am back to tweaking tunes that work best with ATT and Bill's cam.