So...this may be a long read but i'm trying to get as much detail in...
Hi there !

My 2011 Terrain (2.4L Ecotec) Check Engine light came on a month ago - code was P0013 so i replaced the corresponding solenoid.
I must mention that it seemed a bit slow to respond when accelerating prior to this replacement.

2 wks ago i got a message "Engine power is reduced" while on my way to work. I live 4 miles from work so i carried on & noted as it struggled all the way. To get up to 45mph i had to release the accelerator and go again...almost as if i was manual shifting.
Unsurprisingly, it shutdown halfway home after work and refused to start. Called a friend for help but it started as he was arriving and limped for a quarter mile before shutting down again. He pushed me to a safe spot and we went under the hood looking.
Codes returned immediately were:
P228D - Fuel pressure Regulator 1 Exceeded Control Limits - Pressure too high
P0700 - Transmission Control Systems (MIL Request)
P0089 - Fuel Pressure Regulator 1 Performance
P0016 - Crankshaft Position Camshaft Position Correlation bank 1 Sensor A
P2534 - Ignition switch Run/Start Position Circuit Low

Nothing we did helped other than wait, It seemed to start after a period of about 20 minutes & i managed to get it home with only 2 more shutdowns.
I did some reading, looked up the codes (some on here) and decided to use my extensive 2 wks knowledge as a mechanic to replace the timing chain, Crank & Cam position sensors. If you die laughing i will not be held responsible !
The videos were great so removing the mounts to get to the Timing Chain Cover seemed the greatest challenge.

Now here's the crux of the matter; I started it Sunday night & then Wednesday night to roll out & then back into the garage (40 ft), Thursday morning i started removing what was necessary to get to the valve cover so i could check if the timing chain really needed replacing.
I'd purchased the position sensors but was waiting to check before getting the timing chain kit.
Last minute i decided to 'limp' it to my friend's for better space and tools so i reassembled.
At this point IT WOULD NOT START.
He came by, we checked the chain and it appeared ok. Good tension.
I replaced the upper timing chain guide since it was obviously worn. (seems the engine was worked on and this was not replaced)
replaced the valve cover with new gaskets, replaced the sensors and cleaned the throttle body.
NO START.
The engine turns but will not kick in. Instead of the regular undulating sound of an attempted start its more of a smooth turning sound.

Checked the Fuses.
Coils sparking
New plugs (3 weeks old).
I've checked connections and plugs to see if i missed or left something disconnected. All looks good.
When turning the key, it will not auto-return to position 1 when released. I have to switch it off myself.
I tried jumper cables from my other car in case the battery was getting weak but no go.

What did i miss ?
Could this be that the timing was already off & i disturbed it with the changes ?
Any help i can get is appreciated.
Please pardon the length.

It sounds like you are doing things in the proper order, starting with the lowest code first, usually that should take care of the rest but you also have that fuel code, and you need fuel as well to make the engine start. You said you have spark , but it does not sound like you have fuel. That would be the next thing I would start with.

That had me thinking a bit. We disconnected the fuel line where it connected on the right side of the engine...hose with the lil white push clip.
I thought i was supposed too see some fuel when the key was turned but none came. At the store i was told that bulb i saw was not a filter, the filter is in the tank.
Now i wonder, if i'll have to change the filter and pump. You have reinforced another possibility.
Thanks for your reply.

By chance have you even run your vehicle very low on fuel ? I ran out of fuel with an '89 Buick, and the fuel pump burned out at the same time. Coincidence...I think not - the gasoline helps to cool a in-tank fuel pump, and I probably caused the fuel pump to fail.

That's a possibility too, always told my daughter or anyone driving it to always top up. Its a great habit to have. With the recent hurricane scare i didn't need to join the long fuel lines :-).
Who knows, it may've happened although i've never seen it go below a third.

Don't be in too much of a hurry to change things in the Tank, you need to do a deep scan of this vehicle. Sometimes the security system that built in which incorporates your keys may not allow the fuel pump to activate. I would check all of these areas first with a quality scan tool and see what else is going on. You also mentioned your key so its possible that this is all related. It would be a bummer to replace some things unless you were sure. Please let us know what you did and what you found.

I'm in no haste to get into the tank. I'm getting fuel from the schrader valve & i hear the pump hum when the key is switched on. I'll be checking all relays and fuses to see if i missed something.
I hope i can come back with it fixed.

I'd be focusing on that P0016 code if it's still present because if the engine's out of time it's not going to start. When you verified the chain did you verify the timing marks were properly lined up (by hand-turning the engine and watching the marks)? Maybe it jumped a tooth? You said you replaced one of the guides because it looked worn. Maybe that could've caused enough slack? I've always wondered about those Tensioners, too: Are they maintaining enough tension on those plastic guides at all times to keep the chain from slackening enough to jump a tooth?

As for the "high" Fuel pressure ... I'm not near my manuals so I'm just guessing here, but I wonder if repeated cranking of the engine without a successful startup could cause that code to appear?

I've been messing with this on my days off when i get time hence the long time it took me to be back here. Really appreciate all the stuff i've learned on here.

Ok, so after replacing the 2nd Cam pos. sensor, ignition switch & trying a different Fuel system control module I still had the same result.
I took your suggestion Colt Hero & decided to check the timing marks. they were off. Hand-cranked it and thats when the sag in the chain appeared (between the Cam sprockets) so it apparently jumped a tooth or few.
Before going there tho i did a compression test after which that was the next step.
I was hoping the valves weren't bent so next i did a Leak down test. 100% loss on 1, 48% on 2, 15% on 3 & 93% on 4.

Now i search for a new or new to me replacement. Dang the prices are up there !!!

I've noticed the 13-17 engines can be had for less than $1000 but the '11 is twice that or more. What gives ?
Is it possible to fit a newer model in and be done with it ?
What would need or could be changed ? Intake ? Exhaust ? ECM ?
What are the odds of having a smooth, trouble free install ?
I've also considered tearing it down to install new valves & cylinder head.
Just weighing my options to see what works best pricewise.
Leaning on the extensive experience in here

Thanks guys !