Have 2008 HHR 2.2, Automatic, just turned 100,000 miles, NO CODES… started missing a little about a weekand a half back. Has some hesitating and missing during accelerating at first start-up in the AM at low speeds… and later after warm up around 40, 50 – 60 MPH at times of accelerating. At a stop, in park, engine hot, it is hard to get the RPM to hold steady at 2,000 rpm, it falls back to around 1200-1500 RPM when you try to slowly move up to 2,000. When you try to hold it steady at 1500 RPM it jumps UP to 2,000. The engine missing is getting worse every day for the last 2-3 days.

With engine hot, mostly noticeable at a consistent speed when slightly accelerating, clears up as engine speed picks up. Have tried cleaner in the gas tank for a fill up, couldn’t tell it worked. So far NO problems at stop lights or take offs, no stalls or dying’s. NO starting problems.

Replaced original plugs at around 95,000 with factory AC Plugs. Weather here is warm, near 80 degrees today. Been trying different gas and grade, have 92 oct. - grade the last fill-up (NO CHANGE). Someone asked if it feels like it’s in the Engine or Transmission… I think it’s an Engine miss from fuel or spark.

Again NOT ALL THE TIME… NO CODES… gets better as engine warms up in the AM and after cool down during the day time, after it warms up. Without a CODE it’s hard to find a starting place. I will go over the engine compartment for the obvious tomorrow, wires off, fuel pressure, injectors, disconnect the battery for 5 mins. etc.
Hope you friends can point me in the directions to go or have been there.
Thank, JC

 

I don't know how there could be NO codes if there is a miss, maybe no CEL, but there should be a pending code after the first miss.


Check the plugs for color and deposits, visual will tell a lot. Did you use AC/Delco plugs.

 

x2 on pulling the plugs and seeing what they look like (AC Delco's installed ~5000 miles ago).

Check the spark plug recess for moisture/water etc. BEFORE actually removing the plugs.

 

This link doesn't seem to be related, but read it anyway:

P0700 - OBD II Trouble Code

 

I don't know how there could be NO codes if there is a miss, maybe no CEL, but there should be a pending code after the first miss. - - - ARE YOU SAYING THAT I NEED TO USE A SCAN TOOL / READER? BECAUSE I WAS THINKING THAT THE CHECK ENG. LIGHT CAME ON WITH ANY PENDING CODES.


IS THE CEL THE CHECK ENGINE LIGHT ON THE DASH BECAUSE IT IS NOT ON NOW BUT HAS BEEN ON (AND IS WORKING NOW) BEFORE FOR OTHER PROBLEMS.


Check the plugs for color and deposits, visual will tell a lot. Did you use AC/Delco plugs.

OK WILL CHECK PLUGS AGAIN, HAD THEM OUT ABOUT 800- 1000 MILES BACK WHEN I DID THE CHAIN TENINOR AND THEY ALL LOOKED GOOD. YES USED AC/DELCO PLUGS LISTED FOR THE YR AND ENG.


THANKS FOR YOUR REPLY DON

 

You replaced the chain tensioner just before the problem started?

 

You replaced the chain tensioner just before the problem started?


NO, THAT WAS A FEW MONTHS BACK AND THE PLUGS LOOKED GOOD AT THAT TIME...
BUT FOLLOWING DONBREW I WENT AND HAD THE CODES READ OFF THE ECM AT O'REILLY AUTO (AGAIN, THE CHECK ENGINE LIGHT HAS NEVER BEEN ON). READING THE ECM IT SHOWED 2 CODES: DTC PO300 AND DTC PO304. CYLINDER #4 SHOWED A MISFIRED DETECTED.


SO WE ARE NOW DOWN TO ONE CYLINDER WITH A MISFIRE... THAT'S BRINGS ME TO #4 COIL, PLUG, OR INJECTOR (OR COMPUTER PROBLEMS OR OTHERS BUT PUTTING THAT ASIDE FOR NOW AS I'M THINKING INJECTOR OR COIL). WILL TEST THE INJECTOR, THEN COIL, THEN PULL THE PLUG (AS LOW MILES ON IT). IF #4 INJECTOR BAD WILL REPLACE ALL 4... (I FEEL IF IT'S THE INJECTOR, IT IS DIRTY FROM USING CHEAP OR BAD GAS, NOT WORN-OUT).


WHAT I LEARNED: CHECK ENGINE LIGHT DOES NOT ALWAYS COME ON WHEN HAVING PROBLEMS, USE THE SCANNER TO LOOK FOR CODES.


BE BACK AFTER MORE TESTING OF PARTS....

 

I'd put inspect plugs first on the list.[/I]

 

Quick tip on swapping the parts - SWAP coil and or injector with other cylinders to see if the problem moves. ie: coil #4 to cyl 3, and injector #4 to cyl #2.

 

I'd put inspect plugs first on the list



OK TOOK OUT THE #4 PLUG AND FOUND THIS: CENTER AND SIDE ELECTRODE LOOKED GOOD, COLOR STARTING TO TURN LIGHT BROWN FROMSTOCK WHITE. NOW AROUND THE THREADED BASE- BARREL WHICH JUST REACHES INSIDE THECOMBUSTION CHAMBER, I FOUND DRY, BLACK, CARBON. HARD TO WIPE OFF BUT CAME OFFEASY WITH A KNIFE. LOOKING INTO THE CYL. I SAW THE TOP OF THE PISTON WHICHLOOKED DRY AND A LIGHT TAN-GREENEST-GREY COLOR, IT WAS NOT BLACK INCOLOR. THE OUTSIDE UPPER WHITE PORCHLUM LOOKED GOOD, NO CRACKS OR CARBON. CAN’T SAY I FOUND ANY THING UN-NORMAL LOOKING.


NEED TO PULL THE PLUG OUT (AGAIN), PUT IT ONTHE COIL WIRE JUST LIKE IT IS SET UP TO RUN IN THE CAR. HOOK –UP A GROUNG WIRETO THE BASE OF THE SPARK-PLUG, UN-PLUG THE INJECTOR AND CRANK THE ENGINE TO SEEIF THE PLUG WILL SPARK IN TIME AS NORMAL. AGAIN, EVERYTHING IS OUT OF THE CYLHEAD SO YOU CAN WATCH IT SPARK AS IF IT WAS IN THE ENGINE WORKING AS IT WOULD NORMALLY.IF IT WORKS THEN THE COIL, COIL WIRE AND SPARK PLUG ARE OK AND ALL IN PROPER WORKINGORDER.


THEN CHECK THE INJECTOR WIRING AND ECM WITH ANOID TEST LIGHT… IF CHECKS OK THEN TRY TO CLEAN THE INJECTOR OR REPLACE THEINJECTOR.


YOUR INPUT ON MY PLAN, SHORT CUTS WELCOME ASALL YOUR THINKINGS
PS… THE CAR SEEMED TORUN BETTER AFTER THE PLUG INSPECTION AND I PUT IT BACK TOGETHER… BUT WE ALLKNOW THAT IT WILL RETURN MISSING TOMORROW MORNING AS THIS IS HOW THESE THINGWORK… NOT MY FIRST RADIO. MACHINES… GOT TO LOVE THEM.