Random Hesitated/stumble on start-up

[Yeti_Owner]

Betcha it's the intake manifold gasket..

Edited - nevermind, saw you replaced that already.

 

[97SilveradoHD]

drove the truck around quite a bit today, with several stops and re-start ups. each time the truck fired off on just a quick flip of the key, just as one should expect. then the last stop i made i had the truck idling for roughly 10 minutes, shut it off. 10 minutes or so later i went back to start it, and the starter cranked for a bit longer than normal. engine stuttered for a quick second, idle picked up and settled down, and i was on my way... I still can't find any certain circumstance that makes this happen, maybe I'll pay better attention...
I'm almost to the point where i want a respected mechanic to check it out, problem is that it only does it randomly, so diagnosing is a real *****...

In other news, i got my super 40's installed today! Loooove the way they sound. No drone, no crackle, just a deep powerful growl.

 

[DAC_CFH]

Unless you have a wire that has excessive resistance somewhere-

Glad to hear about the super 40s though!

 

[TylerZ281500]

Unless you have a wire that has excessive resistance somewhere-

Glad to hear about the super 40s though!

im sorta wondering that as well. ive had engine issues for awhile before too as i have to had to fix the prevous owners creativity, apparantly he did the ground strap delete mod. if those arent workng right maybe your ignition and starter and all engine electrical will get cooky? im just pulling that out of my rear but maybe.

nvm u mentioned that arlready

 

[97SilveradoHD]

i left the factory ground strap from the motor to the frame in place, and just added a new one from the block to the frame. That seems to have helped some, i don't think it solved it though.... Also the temperatures have been heating up around here, so maybe that's influencing it as well, idk....

 

[DAC_CFH]

Wiggle test?

Leave the truck running and wiggle as many sensors as you can. unplug any suspicious ones and check for corrosion. Do you know how to do voltage drops on wires? Look over at the12volt.com for some really good resources on electronic troubleshooting. check all your relays see if any are getting hot or if anything changes when you touch them.

 

[TylerZ281500]

sure its not a vacuum leak, did you do the starting fluid test?

 

[97SilveradoHD]

AHHH it strikes again... went and made two stops this evening, first stop was roughly 15 minutes. came out to the truck, flicked the key, stumbled up to maybe 7-800rpm then died. cranked it up again, and it stumbled to life and idled pretty poorly. I gave it a few seconds and drove off, everything was fine. Next stop was around 15-20 minutes, started up OK (not great) then the idle speed danced around from 500-800rpm for a few seconds, dropped it into gear and drove away. I know this sounds like a dirty TB, TPS, IAC, or even MAF but they are all new (minus TB) and i know they're clean...

 

[DAC_CFH]

Hmm.. I have a procedure you should follow

First make sure it is on level ground. under the hood there is a cap on the rad. remove it.. Have an assistant move the truck back.. and then replace it.. install rad cap on new truck

Just kidding..

I actually really dont know.. Have you checked recently for any stored codes? it wont always throw a CEL but may store data

 

[97SilveradoHD]

Hmm.. I have a procedure you should follow

First make sure it is on level ground. under the hood there is a cap on the rad. remove it.. Have an assistant move the truck back.. and then replace it.. install rad cap on new truck

Just kidding..

I actually really dont know.. Have you checked recently for any stored codes? it wont always throw a CEL but may store data

Haha yaaa...i've thought about it. I have a scan gauge that reads real time data and displays info in digital format. It also checks and clears codes, both present and stored. i always check, but there's never a code