I have a 2003 Honda Accord LX with an automatic transmission and 2.4L ivtech engine. The car has about 128k miles on it, and about 4k miles ago, maybe 5 months ago, it started acting weird.

Here's what's happening:

When I drive the car and after it warms up, it will want to die at an idle in drive at a stop light or anytime I am not putting my foot on the accelerator. It only happens when it is warm, and then for no reason at all it will stop behaving this way and behave normally.

Usually at an idle at a stop light, the rpms are around 650 or so, but when it is acting up, it will jump around and it sounds like it has a real loppy camshaft installed and the rpms jump from below 500 to 700 - oscillating in a somewhat rythmic fashion. I have to put it in neutral, and put my left foot on the brake and hold the gas pedal down to stabilize the rpms at about 1000 for fear of it dying and leaving me stranded... If I put the car in N or P it gets better without having to hold the gas pedal down slightly, but I live in SoCal and do not want to get stranded on the freeway or some surface street.

If it is warmed up and acting this way, I cannot turn the car off or it is very hard to start. Usually I just turn the key, but if it doesn't turn over when it is acting up like this it will only start if I hold the gas pedal down slightly to open up the throttle body when I crank it over.

I have been told it is an air/fuel mixture problem, some sort of pin sensor that senses airflow, and maybe a front engine mount sensor.

I take the car into the dealership for major services and only use synthetic oil, and I baby the heck out of this car because I know it will last for 200-300k miles if I do (my last honda - a civic had over 250k miles on it when I sold it and it ran fine)... Last time I took it in back in November 2010, it was acting up and then when I drove it into the service center it was fine and the technician couldn't find anything wrong with it. It ran fine for about a month, and then started acting up again. It is really frustrating when you explain something to a tech or the service writer and they can replicate the problem to properly diagnose and fix it...

I think it may be a idle position sensor or something, and sometimes I open the hood with it running and flick the throttle body to open up a few times when I park it for a few hours or for the night and then it will be fine for a few days and then start acting up again for no reason...

Please help me out, I don't have a lot of money and can't spend $1000 to get it fixed - it seems like every time I take it to the dealer I spend at least $800 for a myriad of regular services (brakes, fluid changes, etc). I usually take it to the dealer for major service intervals but change the oil & filters myself - cause I can't see spending $50 for someone to change my oil when I bring my own synthetic oil in for them to do the service...

Please help - anyone. Thanks in advance for any help you may be able to provide...

 

Is the check engine light turning on while driving? I would have the codes read at a parts store like autozone. Post any codes on here.

Do you know when the spark plugs were changed?

 

I forgot a few things...

The last service I had done at 125K miles on the vehicle was at an authorized Honda service center was the complete 120K mile service which included draining and refilling (three times) the automatic transmission (seems excessive, and I thought they would have done it @ 90k miles when I brought it into them about 2 yrs prior - but they didn't do that then and told me I should have had it done @ 90k miles and it was so dirty they had to do it 3X's), a valve adjustment/inspection, replacing the oil and filter (I brought my own oil - Mobil1 full synthetic 5/20 (the wt that is recommended) - nothing else has ever been put in the car since new and it is changed every 5k miles or less - I was told by the tech that my exhaust valves look brand new), replace the cabin air filter, top off all fluids, flush and replace fluids in brake and steering systems, adjust brakes, rotate tires, adjust brakes and parking brake, lubricate all parts (locks, hinges, etc...)... Does this seem like it should cost over $750? I trust my local dealership, but I hate to take it in to them cause they ALWAYS end up charing me about $800 whenever I take it in for major PM services - I am a firm believer in PM servicing if you want your stuff to last long, and I never race the car (heck it isn't set up for racing, and I may be able to beat a yugo off the line, LOL). I take really good care of this car and it is just frustrating to have this problem, I am really easy on it, I never intentionally race the engine, I never drive it hard - shoot, I baby this car because my 1992 civic Si was so good to me and I drove the crap out of it - I drove it hard and put it away wet and it kept running with no problems, I love honda engineering, and as an engineer myself I am very impressed with their quality standards and that's why I bought another one - will probably buy a few more before I'm done buying cars... Please help me out!

 

One more thing.. The spark plugs were replaced by a friend right before the last service @ 125k miles.. I replaced them with NGK pre-gapped plugs - what was originally called for...

 

Also.. The friend of a friend who said he was a mechanic started pulling sensors off when he had it running after he changed the plugs. I knew when the car died after he pulled the mass air flow sensor off he wasn't qualified to diagnose or repair anything... I was out of work at the time and my friend said this guys was good and worked cheap - I should've known better because he didn't speak english very well, but I did have a check engine light come on after he pulled off the mass air flow sensor when it was running (it died after he pulled that sensor), but the light went off about 3 miles later after driving it and it was acting fine... So no trouble codes showing up now, maybe there are some stored in the computer, but no check engine light as of now...

 

I do my own maintenance, so those prices seem crazy to me. Plus California is expensive too.

If this was happening with the old and new spark plugs, I think that you could rule them out.

I don't have a lot of great suggestions. Was there any work done on the car right before it started acting up?

I would have the code(s) scanned. Maybe there are some pending codes that didn't trip the check engine light. Its a free service from the parts stores. I would ask if they can read pending codes. I would also have the battery and alternator tested. Hopefully you can get a code that will help you figure this out.

 

I am having similar problems with my accord. i think it might be the alternator or maybe even battery. I'm going to throw my battery on a charger to see if maybe my alternator isnt working correctly. when you start your car does it seem like it cranks over slower than it used to?