Looking through all the old posts on this code and I don't see that anyone has really found the ultimate solution yet. Very intermittently it will throw code P1174, and ONLY when it's been driven at highway speeds twice in the same day. I typically use the same stretch of highway every Saturday and when I'm on my way home I can predict within a mile of when it will come on. When I drive it locally during the week the light goes back off after 4 or 5 starts.

2007 LT2 2.4L with 67K miles.

 

You have a 2007 2LT, 2.4 ltr. and no other codes. I would pay particular attention to the TSB posted in the other thread (and note please, it must be followed without shortcuts). Nine times out of 10 that is the problem.

 

Thanks Snoopy. Any clue why it would only happen when driven twice at highway speeds and come on in nearly the exact same spot every time? I'm serious, it has to be twice (I've traveled at highway speed and it didn't come on until I stopped for gas which was at least 350 miles into the trip) and I can predict it to within 3 miles on my regular weekend drive.

 

Probably because the code needs 2 occurrences to set the CEL.
Put "P1174" into Google and follow a couple of links for full discussion of the code. One of my favs is obd-
Codes.com.

 

I hesitated taking my car in to have the ignition switch replaced under warranty, but the dealer told me when i called that the CA DMV will eventually withhold my registration because of the safety issue, So now about 60 days later, hmmm, i have a P1174, cleared it for now, I have used Lucas Injector Cleaner in the past, maybe time for some more, ? or just replace the injectors, ? guess 106K miles just wore them suckers out.. or the bad gas here in california ate them up, .

 

Okay, I will Google for everybody.


http://engine-codes.com/p1174_chevrolet.html

I recently had good luck getting 4 Genuine GM injectors from a Chinese vendor on eBay, 4 for $88 shipped got them in 7 days.

That was cheaper than having them tested/cleaned. Get the correct ones and note that non-FlexFuel injectors need a new part number AND Tech2 program upgrade.

 

But if u click on manufacturer chevrolet, it says Fuel Trim Cylinder Balance or something like that,, this thread leads me to believe it is Injector related: https://www.chevyhhr.net/forums/prob...balance-43947/

 

I fixed that while you were typing.

 

So maybe just some new injectors hopefully, mine is not a flex fuel and its a CA car,, oh boy

 

Read the TSB and my edit again.