Cliff notes:

1. Pedal feel and response are different, laggy at part throttle
2. Very Poor fuel mileage under the same driving conditions. Half the normal amount.

Recent maintenance/changes:
Oil change, valve adjustment, dist cap and rotor, plugs, wires, fuel filter, RMF header, 2.5" vibrant cat.

This issue has been going on since I replaced the cap and rotor, around the same time I installed the cat. No idea if its related.
Shouldn't I be running leaner if anything since the header and cat?

Seems like I'm getting too much fuel and running rich causing the hesitation and poor mileage...now what's causing this?

Possible causes?
1. ECU?
2. TPS, MAP sensor?
3. Cat?
4. Did something to the distributor when I changed the cap and rotor?
...other input?

Car is otherwise stock besides cai, header, cat, and exhaust. Running both O2 sensors and stock ECU.

 

Does it feel like it's running on 3 cylinders?

 

Take it into a shop that's reputable. Garage5, Evo garage in Richmond...

 

I'm guessing that drive ability would be greatly affected by this. It doesn't feel substantial, at least I don't think so. Didn't even cross my mind.

Going to take the smart approach and drop it off at a good garage. Don't feel like playing any guessing games.
Will report back.

 

How do the plugs look? What plugs and wires did you put in? Poor gas mileage makes me think O2 sensor related.

 

Everything was OEM. Digging into it in the next few days and ill post updates with something definitive.

 

My money would be that it is a bad injector. I had the same issue on a H22A swap I did for a family member. The injectors worked when I tested them, but three of the four flowed horribly. I'm about 1.5 hrs from RC engineering so dropped them off when I was headed to San Diego for the week. I picked them up on the way back and problem solved. Just another troubleshooting tip for you to run down. Hope you figure it out man. Best of luck- cheers!

 

Your right your running rich, the new header and cat is making you run rich, its throwing off the AFR the ECU is programed for. You now need to tune the engine! Try reseting the ECU by battery fuse or unplug the ecu itself for a few mins. But it deff sounds like its runnig rich from the mods you added, anytime you ad a after market parts that changes how the engine breathes its going to throw off the oem settings causing the ecu to run rich to avoid det and lean conditions. Grab a hondata or EMS system of your choice and tune the engine.

 

I'm with him.

 

I'm not so sure a new header and cat would throw things off that much. When I had my GSR, I had an aftermarket intake, header, exhaust, and no catalytic converter and it ran like a champ on a stock ECU. My guess is that a sensor somewhere is going bad. If I had to take a stab at it, I'd look at the MAP sensor.

 

While I agree the car engine is better off being tuned, worse gas mileage shouldnt be THAT noticeable with a header and cat. My R still gets 275-300 miles per tank and I have a header and test pipe with O2 simulator. I did get shitty mileage with the test pipe when I had a CEL for the secondary O2 before I installed the simulator. I also agree that disconnecting the battery for 10min or so will reset and calibrate the ECU and will probably fix the issue.

 

I had a similar issue once upon a time, and the culprit was an O2 sensor.

 

Most likely to be an O2 sensor. Check the obvious/easy stuff first and dig deeper if you need to.

Not sure why anyone thinks it's the header but I don't have much experience there. IMO it's more likely to be your CAI that will effect your air/fuel ratio than the header.

 

UPDATE:

Looks like the problem was the ignitor. The spring inside was bent and seems like it was causing the issues.
It's been fixed for the meantime. So much smoother and healthier now!

Going to keep an eye on the fuel mileage and drive-ability.

Couple of the valves were slightly tight but nothing majour as well.

 

Keep us posted.

 

Just left Honolulu this morning!...if that's where you're actually from?

 

Yessir born and raised. What brought you out here? Vacation?

 

Were you having any unusual starting engine issues? Almost like a low battery start? From time to time, I'll start the car and its not a really slow start but has a super mechanical sound (i allude to the sound when a Transformer transforms, lol) , which is not normal for my starter. Did you take any pics of the old ignitor? Did you go OEM with the new one?

My battery tested good according to my battery tester i have at home, but I really don't trust completely. The battery is about 4 years old. The starter (which is the 2nd one to be installed on the engine) is not the original one but is an OEM re-man'd one, and is about 5-6 years old.

It doesn't make the sound on every start, but happens quite often. I just don't know if an about to fail ignitor would cause these kind of weird starts, I'm having.

 

Nice man!! Went to do the stairway to heaven climb. Usually in Hawaii twice a year to relax.

No starting issues or hesitation when starting. My idle was adjusted through my ecu to be a bit higher as well.

Did you read my old post about my old car having similar issues? Sounds very very similar! My fuel injectors were leaking fuel into the combustion chambers which wouldn't let it fire up right away. Once I got started the fuel burnt off and it idled okay. It drove like crap sometimes from the leaking injectors too. 2 of them were leaking.

It's too bad we couldn't have a mobile ITR team that could go trouble shoot peoples cars around the world. Best job ever?

 

I do remember your leaky injector issue. My starting issue is not like a flooded cylinder type of start. The starter just sounds really weird at times when starting. I do have a flooded cylinder issue when I move my car from like the garage to out in my driveway, sometimes starting it again after a short distance like that it will have a hard start and then idle returns to normal once I rev it up a few times. lol, yeah, there should be a type r rescue team, I would definite watch a reality show like that, lol.