thegingerman

Ok so sorry if this has been posted before I read through as many posts as possible before saying F-it. I have a 2002 civic ex 4dr 1.7l vtech no mods as far as i know. the car was driving fine and then one morning after i start it and put it in gear and give it some gas it starts to die as if it is starved for fuel. the engine will lose rpms until about at 200 and then start to recover all of a sudden the engine will have full power, after the car warms up it does not have any problems with acceleration at all. it does this after sitting for at least 4-5 hours. i decided to start the car one morning without putting it into or stepping on the gp the car idled fine for about 3 to 4 minutes and the started to stall until it hit about 200 rpms then revved up to roughly 2500 to 3k rpms the settled back down to regular idle rpms drove the car no issues with bogging stalling. it seems the car isn't getting any fuel and them all of a sudden the fuel kicks in but i was thinking this could be a spark or timing issue as well. i was just wondering if someone may have had this issue and knew how to fix it. i plan on doing a k20 swap in the future so just need to keep this car running into the funds come in.

ezone

Disconnect the front (primary) O2 sensor.....then drive it through the same scenario a few times to make sure the problem is gone. If so, replace that front O2 sensor.


Yes disconnecting the sensor will make the CEL come on, ignore it for now.

thegingerman

Hey ezone thanks for the suggestion I had actually found out by looking at google images for my car that the header that's on the vehicle doesn't have a port for the upstream 02 sensor so in other words it's missing. I'm getting a new header and upstream o2 sensor soon

ezone

I thought you said no mods as far as you know? Got pics?


Your primary (front) O2 sensor should be in the pipe below the "header" (which is probably the stock tube manifold for an EX).
The secondary O2 sensor is in the middle of the cat.

thegingerman

Ok so after getting more time to look at the car it does have both 02 sensors the google images i was looking at as a reference were for moded cars lol duh. Neways i am still having the same issue though letting the car warm up is no longer getting rid of the problem. there are newer issues though as well. now the car sometimes will not accelerate unless i have the gas pedal fully pressed. also the car will sometimes lose acceleration when trying to go faster than 80mph when you hit 81 you lose all acceleration, when the car gets back down to 79 you then gain all acceleration, i was able to get the car to stay at 80 but then the car started to jerk/buck. sometimes restarting the car will get rid of the mph issue sometimes it wont. also the car shift points will change sometimes as well. sometimes i can get to 20/25 mph in 1st before changing gear and then sometimes i will get to about 15 mph and the car will lose acceleration until i shift to 2nd, 3rd, 4th etc etc

NDNV

Now when you are describing trying to maintain a constant speed at 80 mph but experience bucking/jerking or hesitation? it seems to me that this may be a symptom of a faulty EGR valve or clogged EGR system. Some have reported that it feels like driving over a washboard type road when their EGR valve or system is faulty.