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Two months ago we purchased a 2012 LX 5-speed manual sedan with ~105,000 miles. We are the third owners of this vehicle. Had the local dealer check it out before purchase and they came back with brakes and a few other minor items. No codes were stored, no fluid leaks, the clutch is solid, and it is treating our son reasonably well.

The one issue I am now wanting to resolve is a hesitation that can be felt when accelerating, cruising, and decelerating. It does not feel like it is surging...more like the throttle is inconsistent or searching causing a small stuttering, sputtering, or hesitation feeling. Observations so far:
- Issue occurs in all gears
- Heavy acceleration bogs down for a few seconds, then takes off
- Engine "stuttering" can be felt on all highway trips when maintaining constant speeds
- It happens both when using the gas pedal and/or the cruise control
- Turning the ECON mode off makes the problem seem worse
- Turning the A/C on also makes the issue worse, more noticeable
- It can be felt even when OFF of the gas, going down the off-ramp from the highway
- Gas mileage has been reasonably good - low 30s in town and upper 30s for longer trips
- Oil appears to be slightly over-filled by ~1/2 quart...planning to drain and fix this weekend
- No codes are stored and the CEL is off
- The clutch seems good with no problems getting the car moving or shifting
- The engine idles well / steady with the AC off, small reduction or variation with the AC on
- We have not taken it back to the dealer for any diagnosis...yet

Current ideas and plan of attack:
1. Clean the MAF sensor
2. Test/reset the throttle position sensor (need to research how to do this, if it is possible)
3. Replace the plugs - suspect the current ones are the originals
4. Test the coils (also need to research how to do this properly)

I do 98% of my own repairs at home. We have a 7th gen 2005 LX SE manual approaching 170k miles, running well with no current leaks. Credit to this forum for knowledge and DIY articles that have allowed us to keep it in good condition - oil pump o-ring, timing belt, tensioner, water pump, main seals, cam seal, cam plug, engine mounts, clutch, flywheel, axle seals, power window wiring, vent stop valve + evap canister, etc. We also own a 10th gen 2017 EX-L CVT sedan hatchback with ~27k miles. Only normal maintenance on that one so far.

Looking for other ideas and input from the forum users. I have used the forum search feature...most seem to point at the transmission (automatic) which this 2012 does not have. I'm leaning more towards MAF and throttle position sensor type stuff at the moment. Unsure about plugs and coils since I suspect these would trigger a CEL code (maybe not?). Open to other suggestions and ideas - please share your thoughts. Where should we begin fellow 9th gen owners?

 
Rep Power: 222

Replace the plugs, and clean the maf, and any other intake sensors. I wouldn't be worried about the coils and TPS personally

 
Rep Power: 0

Thank you Colin. Both on the list for tomorrow.

the following thread seems to be the closest description to what we are experiencing. It still makes me question the coil on plugs - https://www.civicforums.com/forums/3...dder-jerk.html

 
Rep Power: 0

MAF cleaned and new plugs installed. The old plugs were worn but looked normal - no apparent issues with any of the cylinders. Neither were the root cause, but doing the work still paid off.

While removing the air box to access the MAF, we inspected the air intake tube connecting the air box to the throttle body. Sure enough, a huge crack was plainly visible on the front-facing side. Upon removal, a second crack was also discovered on the backside of the air tube. The local dealer was hard-pressed for parts (back-ordered for several months, COVID supply line issues), especially the throttle body side clamp which I had to destroy to remove the tube. That clamp screw was rusted solid and would not budge even after soaking in penetrating oil. Ended up with an aftermarket Dorman intake and clamps for replacement. Its air box side clamp was super tight and difficult to install, but well worth the hassle.

All reported issues are solved! Stuttering and hesistation are completely gone. Acceleration is solid and no longer bogs down. Gas mileage looks like it may be improving - bonus! The best was feedback from our 17 old son who drives the car - "Dad, it feels like you added a fifth cylinder!" He knows that isn't feasible, but was overjoyed with how it now drives!

Another win for this forum and its members. I had seen a few threads about the intake tube being split...research time well spent!

 
Rep Power: 222

Glad you got it figured out 👍

 
Rep Power: 0

As an update, the car is driving well most of the time. Acceleration is responsive to the pedal and stuttering is not typically felt when using the cruise or the gas pedal...with one exception.

With the heat, we have been using the AC more. The AC is turning on when activated on the panel and back off when the button is not activated. The system blows cold air when on. The problem is the jerky/stuttering/hesitation feeling when the AC is in use. It is most noticeable when maintaining constant speeds in 4th gear (30-40 mph). One can feel it in 3rd and 5th as well, but it is less pronounced. Hitting the gas accelerates well and the car idles well. The hesitation in 3rd/4th/5th gears goes away when the AC is turned off.

Is this random hesitation normal with the 9th gen with the AC on, sucking up some of the hp? Or does it indicate a problem with the AC compressor, clutch, belts, etc? AC is one of the few items I have little experience with.