Hello, all, first time poster.

I have a 2004 civic coupe that has about 135,000 miles on it. The car has been treated gently, and usually runs like a dream (except when I had to have the engine wire harness halfway replaced). Lately, however, in 1st and 2nd gear mostly, when I give it gas and start to ease off the clutch, the engine will shudder, and suddenly fall into gear.

To go into detail, it's not completely consistent. I just had the oil changed and it was smooth for a day, but then fell back into this problem. It's most severe in 1st gear, a little less in 2nd (but can still be just as violent because the car is actually moving at this point) and can be slightly felt in 3rd, but is mostly tapered off. 4th and 5th are totally fine.

Now, it feels like the engine is shuddering. So much so that I'm 90% sure its the engine, but I'm no mechanic, amateur or otherwise.

I know this must be vague, but I know it's not a user error, I've been driving this car for a couple years now and I know how to operate it. I know it's not the tires slipping, they're new and I know better than that. I've done a fair amount of googling and it seems that worn out clutch/disk, bad motor mounts and flywheel issues are causes. My question to you fine folks is how can I narrow this down further before going to the dealership and getting financially taken for a ride? I'm pretty strapped and want to make sure I'm fixing the real problem before I spend money. I'm willing to do any amount and kind of testing, and I like to think I'm bright enough to do so despite lack of experience.

Please, if you think you could have any inkling as to what's causing this, or how I can investigate this further on my own, offer your suggestions. I'm getting desperate, I love this car and don't want to do any damage to it from inaction.

 

Check for the engine misfiring by driving along in 4th or 5th gear sooner than you should, so the engine is turning less than 2000 rpm. Then floor the gas, it should run smooth-- not shudder, etc.

If that is OK you probably need to replace the clutch because the shock absorbing springs in the disk are broken, or there is oil on the friction surface. Can't make a direct inspection for that without taking the transmission out of the car first though.

 

I'm taking to car to work tomorrow, I'll try that. Thanks, I'll reply with the results.

 

So I gave it a try, and at all rpms between 1500 and 2000 at which I floored it while coasting at around 30 mph (clutch engaged the whole time, didn't touch it) there didn't seem to be anything remarkable. The car would jerk forward when I pushed the accelerator to the floor all at once, but not to a degree that's unexpected. I don't think the engine itself is misfiring, but the act of shifting (specifically letting out the clutch and giving it gas) in the first two gears causes violent shuddering.

If it helps, I've noticed it's not as pronounced if I give it excessive power (3000 rpms). But if I try to give it a low power shift, which is supposed to be smoother and more ideal in my book, the shuddering is terrible. Taking off quickly isn't even an option anymore, I have to give it a ton of gas and ease into movement, otherwise it's unpleasant.

Also, it seem to like slipping into full gear from a higher rpm. I'll slowly pull the clutch out while revving and it'll have a lot of power at first, and then all of a sudden the rpms suddenly drop into its appropriate place and it's completely in gear. The thing is, the clutch will be in the same spot as a couple seconds ago.

I know that's vague, but I'm not sure how else to phrase it.