Alright i have recently noticed when i am driving i will let off the gas peddle and the car will jerk/shutter. It seems to be getting worse. So today i did a compression test. They were 195-190-210-230. Im not sure what they "should" be at but i did a leak down on the cylindar 2 and it was 230. I only know the basics of what this could mean so im asking you guys for asistance, this is getting very annoying. Thanks 4 n e help.

 

Car was warm when you did the compression test? 230 makes me wonder...

 

Ya car was warm. Is 230 too high or something?

 

A leak down of 230 means that your leaking 230% of the air that your putting in the cylinder which is impossible. And if you were going to do a leak down test why not do it on all cylinders? Its a pain to get each one to perfect TDC but thats how its supposed to be done. Which one was cyl 1 and 4? You didnt specify which was which.

 

Oh ok haha then it wasnt a leak down. I just put a little oil in the cylindar and it whent from 190 to 230. Sorry or misunderstanding.
But the numbers go from cylindar 1 - 4 or right to left of the engine. 195-190-210-230.
What "should" the compression be at?

 

Ok wat you did was a wet compression test. Since you added oil and comp went up, your rings are a little worn. Usually you want all comp numbers to be within 5-10% of each other. I dont kno exactly wat the comp is supposed to be at on this car. Try doing a wet comp test on all the cylinders and see wat happens, see if they they equilize. I dont want to insult you, but I dont kno how well you kno how to do a comp test. Take out all the spark plugs, and disable fuel, and ign. Then crank the engine over for 5 "puffs" of the engine.

 

Ah ok. None taken, ive done plenty of compression tests for mine and friends cars and have always thought it was called leak down when you put a little oil in the cylindar. As far as worn rings go its not likely to make the car shutter when i let off the gas would it? Its weird it likes it when i give it gas, and then i let off the throttle and it feels like its gonna die.

 

I dont think rings will affect that. Try cleaning your throttle body, and the passages in it. Also check your plugs. It sounds like when you hit the gas and let off its choking from maybe carbon build up and runs really rich. Might as well check it, doesnt take long lol.

 

OEM Spec should be at least 180psi and not vary more than 10-20 points from eachother. Having too high of PSI from a compression test means that there's carbon build up inside the combustion chamber mainly on top of the pistons and probably the valves as well.

Mine were 200psi all across and I've seen healthy engines that put out 230+ psi.

 

Carbon buildup definately could be a cause of it. I have to take my EGR apart and clean it like once a month from all the buildup. On top of that if i really get on it, black smoke pours out of the exhaust and i think i am averageing like 19mpg (running a little rich?)

 

USDMs would imagine can range from 185-200 JDMs 200-220

 

Check your plugs. Sounds like your running rich.

 

Compression seems fine then i suppose. As for the plugs i literally changed them about a week ago.

 

Bump Bump Bumpit up. I need some ideas. Car is running very rich - Emitting black smoke, carbon buildup, and 19mpg avg. Brand new spark plugs, and newer cap/rotor/plug wires. Also found that the car feeling like it was about to die when letting off the gas was a broken front engine mount. Was causing the car to jerk back and forth, it had crossed my mind but i didnt think twice about checking it till yesterday...Stupid me. Replaced the bolt today and haven't noticed it anymore.

 

Check your fuel pressure regulator. If you have a way to check fuel pressure use it at the same time. Your regulator might be stuck closed causing too much pressure, and making you run rich.