T-Rev05EX

Hello all I've been recently having this problem with my 05 Civic ex special edition. While driving usually for the first 5 miles and so on my immobilizer icon starts flashing I lose acceleration and have to put my car in neutral and start the car again while rolling, the car always starts up fine but it's really frustrating dealing with this problem. I've gotten the battery checked from three different places and they all say it's good. I've cleaned the terminals and the cable connection to be sure it wasn't the battery. But the keys and the immobilizer are both less then 2 months old and I programmed the keys myself using my xtool x100 pro I don't understand what could be causing this problem. At first I thought maybe it was the key so I switched to the second key I had and it ran great no problem but the next day I tried driving it to work and the same problem happened with that key as well. Are the keys bad or is it something to due with my relays? Again it's a completely brand new ignition assembly and keys please help me figure this out I can't get to work until this problem is resolved and I can feel safe and confident in driving my vehicle again.

T-Rev05EX

So I've had this problem with my 05 Civic EX Special Edition ever since I bought my car off of the previous owner in February ever since I changed the oil in the car it periodically will not rev past 4000rpm when I did the first oil change on the car (which was immediately after I drove it home) the oil was black and I mean you could shine a light through it and still not see through it. The check engine light will pop on but gives me a PO2646 code saying that rocker arm A is stuck open or stuck shut but every time I change the oil the light clears itself but I can only get about a gas tanks worth of driving out of it (400-500 miles) before the problem comes up again and I have to change the oil again now I've gotten a new a new oil pressure sensor and installed it and it didn't help I took the gasket out of the oil pressure solenoid cleaned it and it ran good for about two weeks but the same problem came back and the crazy thing is that the oil turns black really quickly I'm talking about like with only putting 300 to 500 miles on after the oil and filter changes I also feel like I'm losing oil last time I only got about a quart of oil out of the car but I have no leaks car doesn't smoke when I drive it no oil spots on the street or concrete. But the problem isn't only that it won't rev past 4000 it also lets me know before hand that the CEL is going to turn on by giving me symptoms usually in first and second gear or in 4th and 5th the car will randomly lose acceleration and clunk really hard back into acceleration almost like I did a really hard or rough shift but while it's already 2000 to 3000rpm into gear. Or sometimes I'll be going 50 or 60 and I will let off the gas to slow up a bit and press the gas again and it will speed up but then totally loose power and won't respond to the pedal and to compensate I have to downshift and upshift just to try to get the car to accelerate again. At first I thought it was the clutch but it goes into gear and drives fine I've been dealing with this same problem off and on for about 6 to 7 months now and I'm so frustrated and annoyed by this same problem that I'm about ready to throw my car in the crusher just so I can be done with this headache but I love my car it's my first manual car and I treat it with the utmost respect whenever anything goes wrong I'm always fixing it as fast as I can I'm just tired of treating the car right and in return it just taking a crap on me please please help me out with this guys it would be greatly appreciated thank you.

xRiCeBoYx

iTrader: (22)

Sounds like you did everything except for address the problem that your ecu is throwing: the rocker arm

The CEL is causing your car to sit in limp mode (i.e. won't rev past 4000RPM to help prevent any damage to your engine)

Here's a quick and easy way to check it: pull your spark plugs and pop off the valve cover. Rotate the engine using the rank pulley (CCW direction) and see if your rocker arms are moving correctly.

T-Rev05EX

Thank you xRiCeBoYx for the advice I'll check the rocker arm and get back to you

ezone

Alternator mounting bolts are loose?

Don't ask, just check them all.

Alternator is running without sufficient grounding.....loose bolts, bad block/trans/body grounds....and if the problem is not fixed it will turn the PCM into garbage.

EDITS: Leave scanner connected while driving....and see if scanner loses communication with the engine computer while the immobilizer light is flashing while driving.

Just found the OTHER post...that doesn't mention the immobilizer light.
Merging threads....and moving threads. It's gonna look funny.

The P2646 code can set when the oil gets too low, topping it up may be all you need instead of changing oil.
Actually, check the oil at every fuel stop and refill it BEFORE it sets the code.
If it's drinking oil and not leaving puddles, it's might get kinda expensive to fix the right way.
You may have discovered why the previous owner got rid if the car.