Rep Power: 0

So i have an 01 Civic EX with 188k miles. Has an AEM intake, megan racing headers, and megan racing full exhaust. Recently, about every 2 or 3 days, i try to leave for work in the morning, temperature outside about 60 degrees, and it wont start. I turn the key and the dash lights up but no sound from the engine. It starts right up when i jump start it and it will start up every time after that for about 2 or 3 days then it happens again.
About everyday when i first start the car and put it in first gear the engine bogs in and out. Acceleration stops for about 10 seconds, even when gas pedal is to the floor i get no acceleration, no engine sound, no rpm's. I keep pumping the gas pedal then 10 seconds later, all power restored, accelerates great.
Check engine light throws 'random multiple misfire' 'cylinder 1 misfire' and 'cylinder 4 misfire'.

I had the battery, alternator, and starter tested at local parts store, all are up to par.

Changed and gapped spark plugs a month ago, replaced all ignition coils a month ago, changed oil, brake fluid, clutch fluid and power steering fluid a week ago. 2 new o2 sensors about a month ago.

Any insight would be appreciated. Im not mechanically inclined, nor am i challenged. Teach me something and i will catch on.

 
Rep Power: 0

Those two are related.

What plugs did you use, and what did you gap them to?

 
Rep Power: 0

Plugs are ngk, copper ones i believe. The gap is right between 1mm and 1.1mm

 
Rep Power: 0

If it's a copper-electrode plug, then it's not the correct one. The correct NGK is PZFR6F-11, a platinum plug. These coils are pretty particular about having either the right plat Denso or NGK plugs, and *not* touching the gaps. They are gapped correctly out of the box.

If your parts droids make a habit of dropping their plugs, then check with a known good gapping tool. But make sure that gap is 1.1mm.

 
Rep Power: 0

Well i put in some new OEM plugs and misfire code went away. Still bogs in and out when i first start it up. Also getting p0420-bank 1 code. Let that fun begin.

 
Rep Power: 0

Yeah 0420 is a cat code, and a clogged one is the most likely cause. New cat, or j/y cat from a newer EX...

BTW, it's not lost on me that '420' here, means the engine can't breathe.

 
Rep Power: 0

Where would the cat be? Right after the headers? I have this exhaust on:
http://www.meganracing.com/product_d...d=154&catid=13

Theres no cat anywhere along the exhaust so would it be after the headers? Please enlighten me.

 
Rep Power: 0

On a cat-back system, the Megan part starts after the cat. The stock system has a downpipe with a cat at the back of it. The upstream sensor hooks up at the front of #4, the downstream obviously at the rear. <<Link

So really, the system only reduces backpressure AFTER the cat, which is how they're legal (noise aside). The stock system has a shorty 4-1 that bolts to a downpipe that has the cat integral to it, so it's not the easiest exhaust to get power from, without custom-fabbing your 4-2-1's long-pipe headers (my preference for street system) to the cat.

TL;DR -- your cat is still probably clogged. Need to see if you can find either a relatively clear j/y downpipe/cat, or a new one, or weld in another cat possibly? I'm not the expert on that last part; the mods in the Mods forum would be the ones to ask.

 
Rep Power: 0

Thanks for that link. Helps to have a visual. I think tomorrow im going to take the cat off and take a look inside. That means ill have to take off the whole downpipe right? Yay labor.. I wonder if theres any way to unclog it if its not in really bad shape.

 
Rep Power: 0

I just got a brain blast! I think i know how it got clogged!

When i first posted i wrote how the engine bogs in and out when i first start the car sometimes. When that happens, i pump the gas pedal until the engine fires up again. When i pump the gas, theres probably no spark, so the raw gasoline flows down the exhaust clogging the cat!

Yay or nay?

 
Rep Power: 150

Nay.

 
Rep Power: 0

Well then! Still dont know why it bogs. Did it today. Im gonna check the spark plug wires. Faulty connection maybe?

 
Rep Power: 0

Well if you ran it for a while with an intermittent spark problem, that richness is what will kill the cat. You get soot from a lot of heat, which can cover the cat's inside surfaces eventually.

Any multi-point FI system will have no need for an accelerator pump (or anything other than sensors to determine fuel injected), so that can't be it.

Plugs/ignition: did you replace with the proper Densos (PKJ20CR-M11) or NGKs (PZFR6F11)? Do the connectors for the coils have proper contact (has been the problem with other 7th-gens before)?