I hate to say it but this thread is about a issue everyone with a Sky WILL have so you need to read and remember this.

Over the past few weeks my car (07 Base) with a lot of mods as most of you know, has a couple very frustrating problems. Now with 92,000 miles on my car and a daily driver, the guys at the Dealer call it their test car for problems they will see in time.

Reduced Power Mode & hard starting.

The hard starting is easy. Its most likely the EVAP "Evaporation Purge Valve" That you can check very easily. The valve is right behind the valve cover on the 2.4's Its on the intake manifold on the 2.0. If you watch the video below that Dave and the crew up at DDMworks made of the 2.0. The tubes come off the same way. Thanks Dave

The best way is to unplug it first then push the center tang of the clip down that is holding it in place and pull it forward to get it off the bracket then you can get it up high enough over the back of the valve cover to get the tubes off. This valve Prices out at 14.00 online to $44.00 at the dealer.

As far as the limp "Reduced Power" mode here is what I did before finding the fix which has taken 4 months!
I tried unplugging every Engine compartment connectors, cleaned them, put di-electric grease on all of them and plugged them back in. It would be ok for anywhere from 2 days to 2 weeks and would do it again. Every time this would happen I would open the hood, move a few wires around or unplug the throttle body connector and it would go away even tho I had to unhook the battery to clear the amber light.
This went on for weeks on and progressively getting worse. The connector at the throttle body felt kind of strange so I pulled all the pins out, clipped a little wire off the end then soldered then back instead of crimping new pins on.
Well as usual now light and good for 2 days then did it again.
I had taken it to the dealer before to check it but they said it could be any of the connectors causing it but they couldn't tell which one but this time it was so bad they narrowed it down to the c100 harness.
Here is where it gets good. They couldn't clear the codes so they knew it was a completely disconnected wire or pin. After unplugging the C100 harness and plugging it back in all codes cleared and it ran great.
I had already had it apart once my self so once they did it and it cleared we knew that was the problem. I already had the wiring diagram but was not sure which wires would cause it. The Technician was great and we sat down and went over the wiring. He showed me which wires causes this problem because they are the only wires in that harness that talks between the gas peddle position sensor, then to the ECM and finally up to the throttle body.
HERE IS THE KICKER! GM does not sell this harness and the only fix it to pull out the connector on both sides of the plug and hard wire (solder) them together.
This is going to be a issue on every one of our cars because these very small pins wear due to vibration and eventually loose there connection.

If you know how to fix this it will save you $300.00 at the dealer. and NO MORE LIMP MODE due to the throttle circuit

Below are some pictures I took of the process. The first picture is where the connector is located the rest are of how I did it then final tape and reinstall. It is under the metal bracket and you have to take the inner fender off to do the job.
If any of you need the drawing and pin positions just let me know and I post the drawings on here.

Attached Thumbnails

         

Great write up and koodos to Dave once again for the infromative videos.

Thanks so much for this!! Not only should this be a sticky we should have more information on how-to's for water pumps, turbos and clutches. Things that go out with normal wear and tear. On a side note, Dave also did an excellent video on bleeding the coolant system thats on youtube as well. Thanks RickyD. Thanks Dave.

I've had my clutch changed twice and water pump once. I dont have a lift to do the clutch myself but have commented on a few things on the clutch. The water pump was under my extended warranty so the dealer did that for me also but have commented before on that as well. I have another project I am working on but dont want to say anything until I get it done so I can keep GaryH guessing.

You should ask a moderator to re-title this thread: "Solution to Hard Starting and Limp Mode".

How long has it been since you applied this fix?

Can one of the Moderators please change the title to "Solution to Hard Starting and Limp Mode" for all of us.

Thank you..

I know it hasn't been long to see if it actually fixed it but since I couldn't even start it with out a amber check engine light or even drive it a block without it going into Limp Mode I am pretty sure it fixed it. No light and no limp mode driving it for 3 days now. If in fact it did not fix it I will make a post right away saying so. Thank you.

Even KNOWING how and what to fix it, I would still pay $300 for someone with the SKILL to fix it.

Excellent write up. Both for those with the skill and for those without. Because the value of a professional isn't in the execution of the solution, but in KNOWING what the solution is. Now we know. And that savings is worth far more than $300.

You are correct my friend. If I didn't have the skills to fix (according to my Wife) pretty much anything. After 4 months and all the crap I went through I would have gladly paid $300.00 to fix it!!
Unless it requires a lift I do all the work on our vehicles myself.

Ok well since I fixed the wires and then changed the EVAP valve I now have 400 miles on her with no check engine lights and she runs great..

Time to maybe make it a sticky Bogie. What do you think.

Still no lights and car is running absolutely great..

does this connector problem was giving you rough idling when in limp mode?

i might have experienced it today...

I have a evaporate valve in the trunk of
My SKY as a spare and the tools to change
it out. This is a eazy fix and BIG nightmare
without it.
It can leave you sit.
LLLFLY

RickyD: did you scan your car for codes at any point? I'm trying to deal with a very intermittent p2138 pedal position sensor code that puts the car in limp mode. I'm thinking this harness may have something to do with it.