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GM Bob
GM Bob, ASE Certified Technician
Category: Chevy
Satisfied Customers: 991
Experience:  30 plus years. experience as GM technician, ASE Master Technician and GM Certified.
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Chevrolet HHR LT: 2007 hhr. My check engine light and traction

Customer Question

2007 hhr. My check engine light and traction control light keep coming on. I had new ignition coils and new spark plugs put on because the code said there was a misfire in number 4. I just replaced them all since it had 87000 miles on it. The car also had 4 new injectors put on by the dealer in June 2014. Two days after I had the coils and plugs replaced, the lights come on again. I took it to the auto parts store and it reads a misfire in no. 4 again! How can that be?
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Bob replied 1 year ago.
Hello my name is ***** ***** I can help.
You need to do a compression test and a leak down test.
I have had several 2.4 engine have bad valve seats. Causing low compression or air leaking past the valve during leak down test.
If it is bad valve seat need to replace the cylinder head and valves.
If both test are ok I would swap you coil and plug with #1 cylinder. Seeing if the misfire code moves to #1 cylinder.
If it still #4 swap the injectors.
Let me know if this helps
Thank you
Customer: replied 1 year ago.
what about the intake and exhaust camshaft solenoids. Could those be it?
Expert:  GM Bob replied 1 year ago.
The cam shaft solenoids and actuators will affect all the cylinders not just one cylinder.
Customer: replied 1 year ago.
when I first had this a couple of weeks ago, the auto parts store computer showed a misfire in no. 4. When I took it to the mechanic, his computer showed a misfire in all 4 cylinders. The auto parts store computer was just a basic one and was wondering if it was just not catching the other 3 misfires
Expert:  GM Bob replied 1 year ago.
When the mechanic was scanning the engine. Did his tool show live misfire data?
If so was all the cylinders counting up on misfire chart?
You only had P0304 code?
Customer: replied 1 year ago.
they didn't tell me that. They just said it was odd the car parts store computer showed a misfire on no. 4 while theirs showed a misfire in all four cylinders. That is what they told me
Expert:  GM Bob replied 1 year ago.
Do you know the code or codes it is setting?
How many miles are on it?
Do you have any engine noise?
Customer: replied 1 year ago.
they did not give me the codes. There are 87000 miles on it and I am a maintenance fanatic. That's why this bothers me. Never had this problem with a car. This has been a problem for a year now. The dealer said it was the injectors last June and replaced them all. Two months later it was on again and this time they said it was the mass air flow sensor. They replaced that. Then in December again and this time they said it was the gas cap. Now again. And the thing is their really is no engine noise and it does not run rough. The traction control light always comes on at idle, while sitting at a light or a drive up window at a restaurant. It never comes on while the car is moving. This problem is really draining me and my wallet. I figured the coils had to be it.
Expert:  GM Bob replied 1 year ago.
Do you feel the engine running rough?
Do you hear a flutter in the tail pipe when idling in gear?
Some times when a cylinder misfire it causes the other cylinder to show a false misfire. Because the engine is running rough.
Customer: replied 1 year ago.
the engine does not run rough. I hear no flutter. It seems to accelerate fine also. And the traction control light only comes on at idle. I drove it yesterday with the check engine light on, but the traction control light never came on. If it sit in a line of cars for a few minutes waiting to move ( as at a drive up window at a restaurant) the TC light will come on. But the car just doesn't run rough.
Customer: replied 1 year ago.
the reason I figured it was the solenoids was the answer you gave to someone with a similar problem to mine. I know someone in auto parts and he can get me the gm solenoids for $30 a piece. It just seemed like a cheap fix and it could work. Like I said, this thing is eating my wallet. I just can't afford to keep taking it back to a mechanic every month. And this check engine light comes on a lot over the past year. I just can't take it in every time because of the lack of money. Sometimes it goes off by itself
Expert:  GM Bob replied 1 year ago.
Most the time when the sol go bad there is a history code set relating to them.
You could put them in they are not that hard to replace.
I still think you should have a compression and leak down test done.
Customer: replied 1 year ago.
I will have the two tests done this week and I will replace the solenoids myself. I'll let you know what happens and thank you!
Expert:  GM Bob replied 1 year ago.
Sounds good.
Keep me posted.
Thank you
Expert:  GM Bob replied 1 year ago.
Just following up see how its going?
Let me know if you need more help
Thank you
Expert:  GM Bob replied 1 year ago.
Please let me know if I was helpful.
Thank you