kappel918

I know these cars at this age tend to be problematic as far as idle can go due to the fitv and tps senser and iacv now i have a 91 honda accord dx and anyways about a year ago every now and then when i would be driving the car would just start accelerating slightly while in drive without hitting the gas and by what i mean lightly is after a minuet of just coasting in drive i can do about 30 or 40 miles a hour but anyways i found out if i put it in neutral while it was doing this it would bounce from 1200 rpm to 2800 rpm over and over for a few seconds and then stop and go down to normal and then later on it became worse and i could get it to quit if i revved it up to 4500 rpm a couple time in neutral and as more weeks went by it became a permanent problem so anyways i've been trying to fix it for a while i have no codes up or anything and here are the things i have replaced to no avail

replaced iacv
replaced fitv
replaced tps
replaced ecu
replaced tcu

and as a side note everytime i do anything that involves the coolant system i make sure to bleed it. and the car only shows these symtoms while engine is hot at operating temp and it idles fine while its cold

as a side note if i pull the intake housing off to get access to the inside of the throttle body there are those two holes infront of the butterfly valve and when the car is surging it is sucking air out of the bottom hole and if i plug it with my finger it stops and the car idles fine

and as a side note it only does the idle surge after i press the gas petal while its hot to better explain i will give you a example lets say i go start my car and let it sit and idle i dont do anything dont press the brake or gas just turn the key over and start it and let it idle for a good hour and the car is at operating temp after a while or so the idle is fine just sits and purs a little over 800 rpm it can do it all day like this ok so everything is fine so i sit in the car and pop the throttle down for a split second now the idle surges over and over and over again..
please help me as i am going through brake pads like crazy lol...

kappel918

ok an update just replaced all the gaskets completly removed everything intake related off the motor and the intake gasket to the motor was in pretty sorry condition as soon as i pulled it off it came off in 8 peices so for what ever reason i couldent detect that with the starter fluid i was bathing the car with but anyways fixed my old idle problem now i have a new one *sigh* idle surges to from 1800 to 2400 at start up nomatter the temp and keeps doing it i bleed the coolant system to no win anyways i took the tube for the intake off the throttle body and inspected the two other holes on the side and if i cover the bottom one now it doesent effect anything *used too before i replaced gaskets that would fix my idle surge* and now if i plug the top hole it fixes the surge and idles like a champ checked fitv valve withen spec any suggestions?

rdbowlin

Kind of sounds a little like what I had, but I did not replace those gaskets, but may look into it. I had the following and it has been more fun than a person should have. Sorry, it is a long bit to read, but I tried to cover all that I could recall that I've done in about 2 months. Maybe some of this will help you? And, maybe someone will mention something that will help me.
When I am going down the highway at 60mph plus, or in town at 40 mph, or even at about 10 to 25 mph I get this slight surge, or where the rpm goes up about 100 and then drops right back down. In town, maybe every block it does this. On the highway, maybe every half mile. When just in a neighborhood where I am almost going while not pressing the gas at all, it does it maybe every half a block. But, sometimes at the below 20mph it can sometimes drop in rpm about 500 and jump right back up. It seems to shift fine.
I have changed the PCV valve, plugs, plug wires, timing belt, water pump, serpentine belts, cleaned the EGR about a month ago, re-charged the AC, new TPS, cleaned the Idle Control Motor, cleaned the throttle body 3 times, run Sea Foam and other cleaners through the fuel tank, ran some Sea Foam through the pcv hose, dropped about 3 quarts of transmission fluid out and replaced with Honda fluid and one bottle of Pro Long(I think that was the name, it is a small bottle), new air filter, changed oil out 2 times in less than 2000 miles as when I replaced the valve cover gasket from oil getting in the spark plug boots I noticed a lot of crusted stuff in there. Cleaned it out, but figured it needed a lot more.
I got the car a couple months ago and I have been battling it almost everyday. Oh, I also replaced the distributor as the old one was getting oil in it. I know I can get a seal get to fix the other one. I plan to do that later.
One thing that started about a week after I got it was the idle looping up and down. I did turn the screw down on the fast idle. Timing is set, maybe one mark above 15 degrees. Idle was crazy, going up to 2000 when I first started the car and a rough start/hard start. Starts easy, just rough.
I replaced the front of the motor mount and the one by the radiator. That took car of the vibration I got putting it into reverse and most of the rough start. I have checked to see if the injectors were leaking and ticking. They do not appear to be leaking as I did the soapy water thing. They are ticking, though 2 to the rear of the motor seemed louder than the the 2 to the front. Maybe it matters, maybe not, or maybe I just could not get my ear there to hear it as well?
All seemed good for about a week other than a rough start. And, it did not seem to be shifting as smooth as I thought it should, or running super smooth. Yes, I have did a lot to make sure the air is out of the system. But, it seems I still had a little in it after I took it on about a 70 mile drive to get the computer to re learn. All in all, only thing it kept doing was that small surge. When I got about 35 miles and shut it off, it started as smooth as one could ever hope it to. It ran as smooth and quiet as anyone could hope. But, the surge was still there.
Once again when I got back I unhooked the battery, pulled the radio fuse and the ECU fuse. Replaced them hoping it was needed that. No, it still does it. I have cleaned most electrical contacts under the hood. There is no check engine light on. Never has been except when I cleaned the the throttle body for which it returned to normal after I ran it a few minutes or less.
That last trip used about a quart of oil which was different. And, I put maybe a pint of less of coolant in it when I got back. So maybe I did not have all the air out yet, which is amazing given the attempts to get it out of there. Had not hardly used any oil, though I know I have not driven a lot of miles yet. I have taken it down the road a couple other times about 80 miles one way and maybe another 40 mile one way and it did not use hardly a drop. So, I am not sure why one trip used a quart?
Ok, this is the one thing that I am wondering about with all I have done and fixed? This last thing started right after I put about 14 gallons of gas in the 17 gallon tank. There is the thought that it might be water in the gas or bad gas or simply I got caught in the change over from winter gas to the summer mix???? I did put a bottle of the RED HEAT when it was about half a tank. It seemed to make it worse as the next morning it did a drop in rpm at idle right after I started it and then back to the surge as I stated before. It has done this most of the starts since. I have about a quarter tank of gas left of this last fill up. At moments it is almost like the problem is gone and then it is back. I have did a lot to this car in the short time I've owned it. I like it, but little things like this bug me.
I did have a mechanic take a look at it after I replaced the distributor just to see if they noticed anything. Oh, while there they did replace the fuel filter as well. Other than they did not figure anything out and I went ahead and replaced the TPS which I am pretty sure is what fixed the looping as the looping did stop at that point.
Only thing left was that the rpms still jumped up to 2500 after the new distributor rather than the 2000 rpm and when they got done, my idle was almost gone as it almost died repeatedly after I got about a mile from the shop. Since they could not get me back in until the follow week, I went ahead and learned how to adjust the fast idle by turn the screw down and cleaned the Idle Control Motor.
This seemed to do it. It was smooth, all was good, then I filled the tank with gas and I got this problem. I have checked for vacuum leaks probably 4 times and I have yet to find a problem. Soon, I'll fill the tank up again, but I am tired of wasting gas trying to idle it, etc to fix it and get the computer to relearn. I can floor it and it shifts fine and takes off like a scared rabbit. So, I do not see any other issues other than this surge and the drop at about an idle speed drive. Ok I typed a book here. I just want to make sure it is all there. I know it is not in a nice order, but I think I've covered it all. Oh, when I had did most of the above work right up to the point of taking it the mechanic, the gas mileage dropped almost an average of 8 to 10 mpg. Not sure where it is right now, but I did recheck the plugs and I had them close to 40 and made sure they were 44 to 45. The old ones I took off were all about 70. I think it was getting close to 30 mpg when I got it, but it had a lot of needs and I went after all of them. Oh, other than the usual exhaust when it is cooler, it does not smoke. Or, I sure hope it isn't as I have not noticed it.

Andrewelmer21

I have a 2000 accord v6. It idles rough and too low. Aprox 500rpms when warm. Also when I turn the ac on, it surges from aprox 400-1000 back and forth. Its rediculous. Any help please. New to the honda and this forum.