need some help

the only mods that are done are: air intake (over a year ago) and exhaust (2.25" w/ header 4-2-1 and dual outlets, no mufflers) just started happening, overnight kind of thing. It was acting up in the mornings for a while after the exhaust got done but it went away for a awhile, but I think that was from the o2 problem, and then it was worse. It almost cut off then but now it is just sputtering for 1-3 seconds and then it picks up, still doing it in each gear. I guess it is in the 2000-3500 rpm range. It is a civic dx d16y7.

also, in the last day or so, I have stumbled onto another problem. I have 2 stripped lugnut studs and need to replace them. I have managed to get them out but need to know exactly how to get the new ones back in. It is one the back passenger wheel w/ drum bracks. I think I saw a big nut on the back of the assembly that looked like it need to com of in order to get it apartfrom the e-brake assembly but was not sure.

Check things like distributor cap and rotor, plugs and wires. It could be a fuel problem. Does it idle roughly?

As for the lug nut stud, they're easy to change. Take off the drum, and you can either take off the hub, or leave it on. If you take it off, you'll need to repack the bearings, and retorque the hub but you'll have a bit more room. Simply hammer out the old stud(s) the new one will have splines on it, line them up and push it in as best you can with your hand, then take a lug nut (if you have or can easily get the kind that the stud can go through) and tighten it down until the back of the new stud looks and feels like the others. If you don't have a lug nut that the stud can go through then use something to act like a spacer.

it doesnt idle roughly only when I am on the gas, and only for a brief few seconds. It is like there is not enough gas getting to the motor but then enough finally gets there and it is fine. Sometimes, if I am just reving it up, it will make a popping sound out the tailpipe and sometimes when I am accelerating.

What do you mean when you say:...exhaust (2.25" w/ header 4-2-1 and dual outlets...)? Where do the dual outlets start from? Do you have a cat? Did you hook up the secondary O2 sensor after the cat?

Sputtering is too vague of statement. So it is idling okay, but when it gets going, it sputters? As "i_a_n112784" said, check electrical. Probably it will show up fine. Then to fuel... It can be burning too rich or burning too lean. First check air filter. If dirty, that can cause burning rich. Second, have someone bring up the RPM to 2 to 3K, where you are having that problem. Stand behind the car and see if you notice anything unusual coming out from the pipe(s). Black smoke says too much gas. Also you should be able to smell gas if it is burning too rich. If your air filter is clean, and this is happening, then most likely is your sensors.
Otherwise, you might be burning too lean. Could be clogged injectors, could be dirty fuel filter, could be slight vacuum leak at intake...
Or it could be back pressure related... Many things to consider...
Or you can take it to a reputable shop and have them inspect it for $80 or so. Hate to say, but the shop guys usually have fancy sensors and computers that diagnose these issues. :mad: (I want them) Sometimes, it's cheaper and faster to do this than replacing and fixing couple of hundred dollars worth of un related stuff, and making the issues compound.
Anyways good luck.

I have a custom built exhaust system, not prefabbed. It is 2.25" w/ 4-2-1 header and dual tips. There is a Y-pipe before the rear wheel, then up and over. One pipe cuts across the rear end of the car and the other is straight out, Hence (dual outlets). The o2 sensors are in the correct spots, one in the header (upstream) and the other is in the cat (downstream) Before I got it done, both sensors were working correctly, afterwards, I had to extend the downstream wires to reach, however, I put the car on a diagnostic scanner and it said the upstream was bad. I just replaced it and the problem still occurs. But it is different now, before it only happened in the morning when I first started to drive and only in first gear and only one time. Now it happens in every gear when I give it a little more gas for instance say passing someone and it doesnt matter if it is morning, day or night.The air filter is clean, new fuel filter, I do have some Lucas fuel injector cleaner and fuel stabilizer that I was recomended by a performance shop, but I have not been able to use it yet because the wheel studs are still not in. I have been lazy with that. I am going to check the plugs and wires, the cap, coil, etc. I was however planning to replace the rail, fuel pressure regulator, upgrading the injectors, new pump, intake manifold, t-body, and getting new lines for the system, and a new cold air intake. Any good suggestions?

By the way anybody who lives in Hampton Roads, Va. The exhaust shop to go is Superior Automotive. Talk to Gary, he will hook you up. He does more than exhaust too, so if you need anything for you ride, check him out. 757-465-4909 www.superiorautomotive.org the site is down for re-construction but will be up soon.

...afterwards, I had to extend the downstream wires to reach, however, I put the car on a diagnostic scanner and it said the upstream was bad... I was however planning to replace the rail, fuel pressure regulator, upgrading the injectors, new pump, intake manifold, t-body, and getting new lines for the system, and a new cold air intake. Any good suggestions?

O2 sensors work by generation voltage that sends signal to the engine management. If you increased the length of the wire, especially the extended portion of the wire had high resistance, it can affect the amount of voltage going back to the engine management.

Here is a link about testing most o2 sensor:

http://www.forparts.com/o-21.htm

But your case is little different, because you really need to check voltage going into the ecu dut to lengthened wire. Your sensor might be sending proper voltage, but by the time it gets to the ecu, the value might be different due to line voltage drop.

I would not try to change anything before you get the problem resolved. Not only those parts are not your problem and you just dumped a lot of money, it may compound your problem and make it worse. Good luck.

thanks for the replies