My daughters 2008 Chevy HHR automatic 4cylinder has always had weak acceleration.. it takes forever to get to the speed limit, and if you are driving on any kind of an incline or hill, it DRASTICALLY loses speed, almost to the point of rolling back down the hill if you are at a turn or stop on a hill. She just got a service and oil change yesterday, and on her way home the car lost acceleration and wouldn't go over 20 mph, so she pulled over, checked her info panel, which only showed check engine, then shut the car off. She waited about 5 minutes and tried to start it back up, but it wouldn't start. It was rolling over, but wouldn't start. Any idea what could be going on with it?

 

Shouldn’t have been ignoring the Check Engine Light. It lights up to tell you something is wrong. Since she failed to get it checked and kept driving it, my guess would be an engine failure like the timing chain broke.
You don’t state how many miles or how long she’s owned it.

Time for a tow truck and a good mechanic.

 

Timing chain gave up.
The oil monkey forgot to hook the MAF back up.
Was the CEL being ignored for the last 1,000 miles?
They are all 4 cylinder; 2,2L or 2.4L?
Digital temperature?
Parking brake always on?
What is forever compared too? How long is always?
Anything that would make for poor performance would light the CEL. If the CEL is on there are codes that will tell what is wrong.
Anybody ever think to look under the hood? Spark plugs, air filter, oil level etc.
Many "my son/daughter" stories include things like they only know how to put gas in it and isn't that a pretty yellow light on the dashboard.
Should have been in the shop the first time poor acceleration and hill handling was noticed. Might have been something that has destroyed the engine.
My 2008 2.2L only acted poorly when it overheated from me mistreating it.

 

Could be a clogged catalytic converter. Like has been said, having the codes read would give some clues as to what is wrong.

 

She bought the car in April of this year and the car has felt as if it didn't have much power when pressing the gas since she had it. It is a 2.2L and when it's MAF sensor was disconnected, it started back up. The codes it pulled up when hooking it up to the code reader are P0016 crankshaft/camshaft position and P0446 evaporative emission system, vent control circuit.

 

And it doesn't have digital temperature and the parking brake light isn't doesnt stay on only the check engine light

 

P0016 is timing chain. Hopefully the valves are not damaged from continued cranking/ driving.

 

You read an accurate coolant temp on the DIC digital display. It's explained in the owners manual.

Absence of a brake warning light does not prove the emergency brake cable isn't stuck or a brake isn't dragging.

But the more immediate problem is the probable failed timing chain, as indicated by quiting after running poorly with a P0016.

It's really important to not try to start it or even crank it, not even let a well-meaning mechanic crack it, until the timing chain is fixed. Which means towing.

Before repairing the timing chain it must be determined if the valves are bent. Repairing those involve removing the cylinder head, so rather expensive. You'll want to decide whether the cost is worth it and consider alternatives.

Some mechanics won't feel confident doing this work. You may need to ask around.

This is the problem with not immediately addressing a CEL. The driver was warned to have the car checked asap. Any competent mechanic should have advised of the urgency of a P0016. The P0446 is trivial by comparison, probably not causing the no-start, and can wait until the timing problem is resolved.

 

There is a digital temp. Read the Owner Manual available via the link in my sig.
P0016 means that the timing chain needs replacing. It means that the crankshaft sensor does not agree with the camshaft sensor because the chain that connects them is stretched. Most people you ask will try to sell you a ne crankshaft sensor, they are wrong.
I bet that it is impossible to fill the tank on automatic, keeps cutting off. That is from the P0446. Probably a clogged up EVAP vent valve.