CX-7 jerky when accelerating over bumps

D

Dvorak

Greenie N00B Member
Hey guys, I bought an old 2007 CX-7 2.3 DISI turbo (manual transmission) with 135k km on it. It drives fine on good surfaces, but has one rather big issue when not. In first gear, when I am accelerating and hit a bump or a pothole, the car starts violently jerking forward and backwards with increasing intensity (in technical terms just like wave superposition). The engine's RPM increase and drop as if I were quickly pressing and releasing the gas pedal. To stop it, I have to release the gas pedal completely and/or clutch in (if the engine were to stall) and continue driving. On even surfaces the car drives just fine and is able to accelerate quickly and smoothly, which leads me to belive that I can rule out spark plugs, injectors and fuel pump. The throttle pocition sensor seems fine too. The air filter is new. The diagnostic shows no trouble codes. Any ideas?
 
Possible MAF sensor or wiring to it is bad. Primary Oxygen sensor is another. Also check basics like ground cables and battery cables.
 
Raider said:
Possible MAF sensor or wiring to it is bad. Primary Oxygen sensor is another. Also check basics like ground cables and battery cables.
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Thank you for the reply. The primary O2 sensor is new, MAF sensor seems fine (no strange behaviour showing on the diagnostic tool)....what baffles me is that tha car works perfectly on good surfaces. I suspect there might be something wrong with the suspension.....
 
Dvorak said:
Thank you for the reply. The primary O2 sensor is new, MAF sensor seems fine (no strange behaviour showing on the diagnostic tool)....what baffles me is that tha car works perfectly on good surfaces. I suspect there might be something wrong with the suspension.....
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Have you checked the plug gap?.026-.028 is what you want.
 
Wondering if you've got a loose connection especially on the throttle body I'd go check that connection make sure it's clean, seated and no frayed wires shorting. Also there's a ground wire near the hpfp bracket (small black wire single strand about 16awg) that's notorious for causing random issues ensure that's clean and tight
 
Thank you, I will check the spark plugs and the throttle body as well as the ground wire & will let you know the results.
 
Raider said:
Sounds good! Happy birthday!
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Thank you!

Sorry for the delay guys. I had the spark plugs changed (just ot be sure) and the throttle body as well as the MAF cleaned. Unfortunatelly, none of these helped....As for the ground wire. I THINK I found it, but didn't find any issues with it.

It is a very strange case, I know. The guys at the shop ran a live diagnostics when driving and the motor seems to be perfectly fine.
 
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