Hi, this is my first post on the forum and I apologize if it is categorized incorrectly or if there exists another thread already. I'd also like to thank many of you for contributing information on this forum that has helped me in the past.

I'd like to preface that I am not a mechanic, I will be as honest as possible and accept any criticism you'd like to dish out.

The vehicle in my garage is a 2009 Chevrolet HHR 2.2L with 220,000 Miles. Original motor (untouched) besides new spark plugs and ignition packs, rebuilt transmission @ ~150k.

The issue that I am experiencing is a rough idle, ENG PWR REDUCED, a ticking sound from the valve cover area which increases in intensity upon acceleration, a "hydraulic-like" noise in high RPM's, lean system, multiple cylinder misfires, an upstream O2 sensor that is not reading, throttle body/accel sensor code, and I believe a camshaft position timing solenoid code.

1. I replaced the throttle body with that of a used one from my junkyard; followed the idle relearn procedure and that fixed the ENG PWR REDUCED for a month but then returned.

2. Haha I noticed exhaust smoke rising from the engine cabin and upon inspection found a 4" vertical crack on the exhaust manifold. I had since patched the crack with liquid steel cold weld and a custom fabricated aluminum sheet clamped over the crack. It has been holding for about a month with many commutes form the Poconos into NYC via I-80.

3. I replaced the camshaft position solenoids (intake & exhaust).

4. I replaced all spark plugs and ignition packs

5. I change the oil & filter regularly

Soooooo with all of these expert repairs, I still experience ENG PWR REDCUCED, still throwing throttle/accel code, the o2 sensor upstream I have not touced, it is still misfiring on all cylinders, and the ticking/hydraulic sound has not dissipated after new oil/filter.

I've never taken my car to a mechanic before except for inspection and tires but I think I've finally met my match. It sounds like bad lifters or gunked up head that may not be allowing adequate oil and pressure to pass through (I did not test oil pressure). This may explain the misfiring and timing problems. Obviously the exhaust manifold was not fixed properly but it is no longer leaking. What concerns me is the ticking and hydraulic-like sound coming from the front top of the motor. The timing chain and tensionor are original.

Good luck. Any thoughts are appreciated.

 

Current Fault Codes:

P0131
P0171
P0300
P2135
B2aaa

 

FIRST: what are the OBD codes. We don't care what the title of the code is (they are different on every reader and usually don't mean what they seem to mean).

Second: don't run the engine until you ispect the timing chain. Sound like you have sometrhing wrong that could be fatal.

Are you sure it was a crack, not the built-in space between #2 & #3 in the header? New/used headers can be had for ~$100. And a cracked flex pipe?

I was typing when you were updating

A. I suspect a cracked flex pipe or you repair isn't good enough.
B. I would check your O2 Sensor wire, it may not be connected properly or laying on something hot.
C. I think the B2aaa means a shorted wire.

 

x2 what donbrew suggests.

The p0300 may be related to the noise you hear - as per the reference to the timing chain issue by Don

The p0171 may be related to a cracked flex pipe as Don mentioned - check that and the O2 sensor wire (p0131)

 

X3,Ih, and Welcome to the site!

 

Thank you everyone and @donbrew for the helpful info, really am appreciative.

I am going to follow up on your suggestions and post results.

For anyone that might be interested, the ENG PWR REDUCED started happening about 2 days after I installed a new battery. I performed the idle relearn procedure several times with no success.

Here's the messed up thing, I reinstalled the old battery that is not strong enough to turn over the engine (have to jump it) and the ENG PWR REDUCED does not happen. How the hell does a dead battery fix it?! I guess I'll be jumping my car every morning...

 

What Idle relearn procedure? Idle for 3 minutes, that's it, according to the Sop Manual. I keep hearing people cite "the idle relearn procedure" I don't know what they are talking about.

That mileage warrants a new chain and guides and tensioners, at least.

Eng Pwr Reduced is because the computer is trying to save the engine from death.

Have the ignition recalls been done?

 

I've attached the GM bulletin for the relearn sequence, but essentially yes idle for 3 mins, off for 1, idle another 3 mins.

No, no recalls were done on the vehicle lol.

I understand it's a safety feature but it's almost entirely caused by the throttle body sensor in most cases and quite frankly I'd prefer the motor to catch fire than be in rush hour traffic when it occurs.

 

From the link you provided:
"This is a comprehensive list for the model year 2007. Older or newer vehicles could differ."

Since yours is a 2009, and I would assume a Flex Fuel model (which the 07 was not), the relearn may be different.

 

That's true, but I couldn't find the relearn procedure for newer models and if it's an automatic relearn it won't hurt to try it anyway.

It doesn't matter to me, the only fix in my situation is to run the car on a dead battery to prevent ENG PWR REDUCED. If I hook up the new battery again, it will reduce power and idle chaotically within minutes of start up.