4000 rpm engine sputtering
 

as the engine approaches 4000 rpm on my 1998 Honda Accord LX it seems to sputter or drop out. But this only happens at 4000 rpm. It was also idling low until I added some fuel injector cleaner, then this cleared up. The car runs fine except for this. Has anyone heard of this or had this problem....

Thanks...

check all your wires... distributor... rotor... spark plugs...

Yeah, sounds like the distributer to me

does it lag after that or just die there?

it lags for a second then kicks back it. It never dies. My husband says its kinda like there is a rev limiter.....

O2 sensor(s)

hmmmm has your car ever been hit on the front passenger fender?
with my car my ecu got shorted out so wheneva i hit around 4500 it would putter and lag past it. basically for me my engine was tryn to go thru its VTEC stage but wasnt recieving the signals from the ECU i had to get a whole new ecu. might not be your problem but thats why i'm asking about the accident

my car does the same exact thing!! at 4000 hey decibel what was the problem with your car now?? because i think my car was in an accident but not sure if that could cause it??

that can be alot of things. 1st check intake air control valve sensor located in front of intake manifold,. another could be faulty spark plug wire, or spark plugs, might be loose. O2 sensors, clogged injectors, fuel filter, or faulty fuel pump. if it has a check engine light, its most likely the o2 sensor or the intake air control valve. good luck.

If its 4cyl vtec does it accel past or act as if its bouncing off a rev limiter. it could be an oil pressure problem. Vtec kicks in @ 4000 rpm on 98-02 accord 2.3 and is controlled by oil pressure buildup. vtec switch clogged, o-ring busted, oil low? Is check engine light on?

I am having the same problem on a 2000 Accord 4cyl manual transmission. My check engine light is on. From what I am reading here, it's either the vtec swith or o2 sensors. Should I try to clean the injectors first?

The chances of your injectors being clogged is slim. it also wouldn't set off the check engine light. Pick up a haynes manual ($15) @ any auto parts store. Helms is a better manual but costs 4x as much and is alot harder to get. In section 6 is an explanation of the use of a jumper wire to read engine codes and an explanation of what the codes mean. If it comes up as an O2 sensor let me know. You can clean them, even though everyone says you can't. Vtec will show up as a trouble code too.

How do you clean the O2 sensor?

Sounds like low oil pressure. Make sure the oil level is full, then try again. VTEC wont engage if theres not enough oil, making the shuddering sensation.

Cleaning O2 Sensor:

Remove sensor carefully (don't lose the metal washer, sometimes it sticks to the manifold)

Fill a glass jar or cup(don't use plastic!) with fuel injector cleaner to a level where it just covers the sensor housing (the part below the threads when the wiring harness is facing straight up). Dont submerge anything that isn't metal. Fuel injector cleaner can soften plastic.

Let it sit for 10 minutes.

Scrub with a stiff toothbrush or plastic detailing brush, making sure to push it into the holes.

Rinse with extremely hot high pressure water and then blow it clean with an air compressor. Be sure to remove all moisture.

Reinstall.

O2 sensors work by measuring resistance in exhaust gasses. Essentially all you're doing is cleaning electrical contacts.

I did this to both of the OEM O2 sensors on my 99 Acc 2.3 @ 160k (it was running rich, showing trouble codes for primary heated O2 sensor malfunction). Car runs smooth as silk and all trouble codes gone. 173K today. I drive 250-400 miles daily six days a week.

Anyone going to object to this method?
I might want to try it before dishing out the bread for a new sensor.

Exactly. If your car is low on oil, it will not rev past 4K RPM's. Check/Change your oil. Especially if it's happening and your CEL is on.

I'm I'm sure you're going to get a lot of people saying it's the vtec solenoid or low oil pressure change your oil flush your oil etc my question is do you have hey maintenance required light on or oil change light on my oil change light has been on for a little while and all the sudden it wouldn't rev past 4000 RPMs it felt like an electronic cut off I don't know if it was fuel or spark anyways just for a goof I reset the maintenance light and my problem went away it could have had something to do with just shutting the car off and on but it works for me maybe it will work for you

Wiring
 

The wiring to the vtec solenoid and the he one near the intake are the same looking plug . The one with double wires in the end connects to the vtec solenoid. This was my issue someone before me did the transmission and did it wrong when they put it back together.