Hesitation,Bog, Flat spot?
 

Hey everyone.

Just picked a 2004 Si with the HFP kit. 75K miles, STOCK besides a K&N drop in filter.

My issues are mainly in 1st and 2nd gear. While accelerating between 2,000 and 3,000 rpms it will bog/hesitate, it feels like just stops making power for a second. No check engine lights, oil was just changed, spark plugs look newer (ngk iridiums). I ordered a new IAT sensor as the one in my intake tube looks bent, somehow. My next plans are to clean the IACV.

I will be using my ultraguage to check tps percentages..

* The car is the same with a full tank of gas or with a 1/4*

Any one have any input? This is so annoying to drive, my rsx was never like this..

Helps!

Thank you

Updates:
*** The car seems to use extremely fast, 60 miles per first 1/4***
* The car is the same with a full tank of gas or with a 1/4*
*Once warmed up, if rpms are held at 1500 or 2000 it misfires, sounds like a slow 2-step.. Thinking its ignition.

9/13- Cleaned IACV and adjusted the tps which is within perfect range... No difference..

Any help out there?

Re: Hesitation,Bog, Flat spot?
 

TPS seems to act normal, but this is testing with an Ultragauge (same as scangauge) I will use my multimeter tomorrow.

Re: Hesitation,Bog, Flat spot?
 

if you're in neutral and hold the revs you can hear it missfire at that RPM?

Re: Hesitation,Bog, Flat spot?
 

Yes I can. But only sometimes. Neutral, rev to 1500 or 2000 and hold and there is usually a misfire.

*Also, sometimes the car idles high..

Clean the iacv?

Re: Hesitation,Bog, Flat spot?
 

Updated!

Re: Hesitation,Bog, Flat spot?
 

Update with more info, someone has to have some input.

Re: Hesitation,Bog, Flat spot?
 

Wow i thought i was crazy but looks like im not the only one with this same problem. I get the same thing when i accelrate in 2nd gear right around 3k rpms. its almost like it sputters for a second nd then picks back up again.. It happens very inconsistently for me.

Im also having the same trouble with my gas. Once it goes under half a tank it seems to just evaporate lol

I've also done all the maintance. Spark plugs, oil, new o2 sensor etc.

Re: Hesitation,Bog, Flat spot?
 

I changed the IAT today because the one in there was bent lol. Drives a tad better, now idles like crap. This is annoying!

Re: Hesitation,Bog, Flat spot?
 

I have the same type of problem when cruising around 3k it bogs for a second and hesistates. Tried all different gas stations thinking I got a bad batch of gas. I know my TPS is good it was just replaced and no other CELs. Only does it once the car warms up.

Its annoying I'm in for an answer also

Re: Hesitation,Bog, Flat spot?
 

Any thoughts on the Coolant Temp Sensor?

Re: Hesitation,Bog, Flat spot?
 

I am also having the same problem, car now has 163k and haven't replaced anything yet , just thought it was how the car drove with the "ivtec" , any thing I could start by doin to maybe fix the problem?

Re: Hesitation,Bog, Flat spot?
 

I doubt this would be the cause if the coolant sensor was bad enough to cause any kind of issue it would almost deff trip a code. Seeing as how you have checked so much already there are only a few places left I would look. It could be one of your coil packs is going bad. When they get hot sometimes they can supply a less than normal voltage if there shorting to something in the head, or just not storing the proper amount of firing voltage. Also sounds like it could be a sticking fuel injector or fuel pressure regulator issue. If the pressure in the rail is not strong enough under hard load you could get a loss of power feel. Goes the same for an injector but now that I think about it an injector issue would almost deff trip a miss-fire code. Hopefully you can get it figured out.

Re: Hesitation,Bog, Flat spot?
 

lol this is funny as fuck becuse i usto own a 2002 civic si .. and from 1st to 2nd it usto misfire and since i had no cat and no resonator it would back fire from the exhaust ... we never could figure out what it was... and i sold it... but i had the same issue with my car.. miss fire hesitation and backfiring !!!

Re: Hesitation,Bog, Flat spot?
 

the flat dead spot betwee n2k and 3 k rpm THE FUCKING PRIMARY 02 SENSOR TROWING NO CEL CODE

A REAL MOTHER FUCKER CHANGE IT EVERY ONE WHO EXPERIMENCE A DEAD FLAT SPOT BETWEE N 2K AND 3K RPM


the fucker primary 02

Re: Hesitation,Bog, Flat spot?
 

any outcome on this having the same problem