Before I get to the problem Ill list the car and the mods done to it, I hope someone out there can help me out because I DONT want to drive my car the way it is right now, I don't know if it will damage it.

First its a modded '94 Civic DX -D16 engine
-Cold Air intake with modded Bypass Valve and Bored Throttle Body.
-18mm iridium spark plug wires w/ iridium red core drag plugs.
-Increased Header size 4-2-1 style, stainless steel lightweight design.
-2 3/4" pipeline size back to the exhaust canister 3" catalytic converter is not hi-flow however.
-Car has been slammed, 3 inches above the ground with adjustable camber and height springs.

Now I havent had much in the way of any problems with this car, in fact the whole modding experience has been great until I was pulling into yesterday afternoon. Normally this car flies, and she is understandably loud with the mods I have done to it. It usually had a nice full bodied overtone to the exhaust, a nice steady one that is... But as I was pulling into the parking lot I noticed a slight fluttering sound instead of a solid tone. When I left that evening I decided to rev the engine up before leaving, I revved it hard and nothing sounded funny at all. However when I took her from neutral and put her in gear and started to go the engine sounded like it was being retarded and the fluttering sound came back. When I tried to open the throttle up on the road I could notice a MASSIVE loss in horsepower and the fluttering in the sound became inttermittent. It would come and go and so would the horsepower. I can normally take this thing up to 80 on the onramp in no time at all but now it is sluggish and no faster than the astro van that is trying to get on the ramp with me, (a very insulting picture).

Today I awoke refreshed and thought that the fuel system had a definite problem and I decided to change the fuel filter and diagnose the system but to no avail. Orginal fuel filter was only a year old and was hardly clogged at all, new one had no restriction at all but did not fix the problem. Then I thought maybe it was the injectors so I bought some injector cleaner additive that you put into the tank but after driving it for awhile like that I really don't know if that is the problem...

Some have suggested an o2 sensor problem but I get no check engine light and am not sure how to diagnose my o2 sensors... So if ANYONE can help me get this car back to running a like a pony PLEASE help!

 

Can you do a compression test on the cylinders? I don't know is a seal somewhere is blown, such that power is being lost through the broken seal.

Are any of the spark plug tips oily? An oily spark plug usually indicates the leak is near that particular cylinder.

Take a look around the cold air intake and make sure a plastic bag or garbage isn't covering it or something.

 

also check your plugs to see if they smell or are wet from petrol (no spark)
i'm pretty sure a lambda sensor fault would bring on a mil.
also, check to see that the engine is heating up to operating temp - half way up the temp gauge on your instrument cluster

 

check your timing.
check the spark plug wires.

 

No trashbags or foreign objects on intake, if a seal had blown wouldn't the CEL come on at least intermittently if not steady? Car does heat up to the halfway mark and stays there. I will see about the timing though... This is such a weird one for me, I have no experience on this kind of problem.

 

Pop off the oil filler cap while it's running and see if you can hear a woshing sound...put your hand over the hole and feel for blow back or blow by pressure...you may have trashed a valve or two or they maybe out of adjustment...that's if a D16 has adjustable valves...start pulling plug wires one at a time and see if you can fine one that makes no difference...if so, that would be the cylinder causing the problem...just a thought...I just went through this with my D15B and I fixed it by replacing the head...good luck

 

Ok I popped the oil filter capped and now I am really scared, air is sputtering out of the cap hole at the same interval as the stuttering. What do I do now, what do I need to replace to have this thing running again? I won't be driving this car for awhile now with this in mind... Any extra help would be appreciated!

 

Anyone know how to repair valves? I have the manual on the car but its not very descriptive...

 

just get a whole new valvetrain... and ahve a machine shop put them in to yur specs.... its worht it.