Huge hesitation, mechanically inclined. Please help

[Chip18]

You can check just about every sensor with a DVOM, you just need to know what the values are?? And dare I say it but a Chilton and or Haynes manual should have that info. And yes you can use carb spray to check for a vacume leak and go ahead and hook up a vacume gauge anyway to see what the motor is doing at idle??

The one sensor I did not see you mention?? Is the IAC ... Idle Air Control motor/valve?? It could have carbon build up on it???

Some info on it

http://www.gmtuners.com/tech/TPS_IAC.htm

Some info on it, if they ran a scan they may still have the data?? Seems like it's a fairly rare failure however?? Looks like it's about a $50 part?? Couldn't hurt to pull it and clean it in anycase.

 

[Brian Wilson]

You guys have been a ton of help. Very Informative member base in this forum.

 

[Brian Wilson]

In other news I finally got a check engine light so my fingers are crossed

 

[02Lightning]

The one sensor I did not see you mention?? Is the IAC ... Idle Air Control motor/valve?? It could have carbon build up on it???
QUOTE]

I didn't think drive by wire cars had a idle air control valve?

 

[Chip18]

http://repairdata.cnlaunch.com/pdf/2013/09/25/91ba623e-0f70-4621-9342-f4c7d469e48a.pdf

I had to edit my original post cause I left out a word.

That is what I found and my buddy at the dealer said the same thing. I'll be driving and all the electronics will shut off and come right back on. The motor has shut off once that I can positively remember. I have a code reader and it throws both the codes in the link. I have replaced the main fuse and and cleaned the easy terminals. I'm thinking next is battery and alternator cables.


Sent from my iPhone using Tapatalk

That is seriously messed up!

I didn't think drive by wire cars had a idle air control valve?

LOL ... I'm going off of concepts of operation of Fuel Injected motors in "general."

I'm certainly "Not" an expert on these motors. An IAC is listed as a replacement part but I have seen T-Belt kits for "Nissans" and "Nissans" ... have "Chains" ... not belts, so there is that.

I'm sure one of the "Chevy Gurus" will confirm if these motors have IAC's.

And ... you have a 02 Lighting??? Awesome Trucks, we have a couple out here ... they only show up in the summer time!

 

[Rocket Man]

@Chip18

 

[Tonyrodz]

Lol!!

 

[Chip18]

@Chip18

I don't get it???

 

[Brian Wilson]

Ok, so after all day testing with a snap on modulus 2 and a tech 2, my car is perfectly fine. Absolute 0 problems. BUT, it still hesitating like crazy. All sensors are working correctly and throttle body is not sticking. The only fault I could find is at certain times, the timing would drop to almost 30 degrees retarded. The timing was all over the place. I know the cam position sensor and knock sensors are working correctly. What else can anyone thing of that would retard my timing?

 

[Chip18]

There is also a "Crank Position Sensor," it's job is to determine TDC. If it's off ... it could be sending the wrong info to the "Knock Sensor" whose job it is to "Pull Timing."