When the do check the pressure, have them clamp the return line with the key off and let the car sit for a few hours. If the pressure drops one of the injectors is not holding pressure.

 

I was driving to work yesterday morning and was stopped at a light and the car died..I started it back up and it was ok until I was on my way home last night from work and it did it again. It was fine this morning to work but on my way home it died twice and again a while later in my driveway. No CELs and it died in my driveway even after pulling the Back up fuse for a bit. I dont want to start throwing money into what it "could" be...
Any other progress on figuring out what this could be?

 

Cleaned out my IAC valve saturday as well as replacing my ratteling cat with one from an 06 (btw, my cat had an "A" on it while the 06 had an "X", wonder why). The element inside had actually been worn down in the shape of the O2 sensor where it had been rubbing on it. I wonder if the element dust/particles caused any false readings or my problem.

Anyway, it ran ok this weekend but it was cooler than normal. We'll see tomorrow when I have to drive it mid day.

Just on a note though, Friday when at work, I ran fine on the way to work but started hesitating and threw a code before I got there. When I went to lunch, it started fine and ran perfect. When I got in it to go home, it started like crap and ran aweful. barely got home.

 

Just throwing this out there bcause I am have pretty much the same problems in my civic, and I have been told by several shops to test the voltage on my fuel pump because it might be bad. So I'm going to say the same to you. Check the voltage on your fuel pump or just order one from Autozone, replace it and if that doest work just return it.
I also have the same suspicion that you have a disconnected, rubbed, or broken vaccum line. The crappy thing about that is there are so many of them it's easy to miss. Hope it turns out well! Keep us updated!

 

Any updates?

Having a similar hesitation problem with a MY 2000 S between the ranges of 3-5.5k without any CEL. It'll stall occasionally at intersections but will mainly hesitate consistently at the other rpm range as mentioned in most any gear, mostly apparent in 3rd under light acceleration. MAP has been cleaned and zip-tied, IACV has been cleaned twice & ECU has been reset but the problem still persists.

Just saw your thread today and will try and get the fuel pressure checked out too but saw this interesting post from S2Kart.

"Iv'e been chasing down an intermittent stumble/hesitation for awhile. The car never threw a code, but would occasionally hesitate around 3K- 4K rpms. I can see the AFR go lean when it does it. I checked all the sensors, but all were good. Seemed like the secondary air system was the culprit since I noticed that occasionally I would also get this sudden and massive compression braking on deceleration (secondary air injection also operates on decel). I checked everything: pump, relay, current sensor, vac. cannister, both valves, hoses, wiring, ECM - all checked out fine. Finally I decided that either the vac operated diaphram valve (which is at the back of the intake mainfold) or the vac solenoid valve (which controls the vac. diaphram valve) must be getting sticky. Turns out its the vac solenoid valve, even though it checked out fine per Helm's and on the bench with a 12V power supply.

Here's an easy way to see if the vac solenoid valve is causing hesitiation/stumbling problems: disconnect the vac line that goes to the diaphram valve and disconnect the air supply line at the diaphram valve also. This will will effectively stop the secondary air from entering the exhaust manifold and will keep the exhaust system sealed at the diaphram valve. The secondary air system will still operate, but the air will just blow out under the hood. Take a test drive and if the stumbling/hesitation goes away, then the vac solenoid valve is probably getting sticky.

What a hard one to solve without any DTCs, but the occasional hesitation issue is gone for good now."

Slows2k, any thoughts on this method too? Haven't tried it yet and will give it a shot.

 

While the air injection system does have a path the the exhaust system, the air control valve has a reed valve inside to block exhaust gases from traveling backwards in the system.

The air pump would have to be on all the time, and the solenoid engaged to allow secondary air flow into the exhaust in order for a fuel metering DTC to set.

The PCM would bug out over the Air pump running all the time and incorrect flow during a cold start 1st. You'd have P0411 and a P0410 1st.


Cyclon's car doesn't have a random hesitation, but a PCM that is constantly adjusting fuel trims outside of it's normal operation range.

Gotta check the basics before getting off on a troubleshooting tangent.

 

C, thanks for the explanation. Going to start weeding through the basics and see what we find.

 

Problem went away since my last post. I've been driving it normally since then with no problems at all. I haven't had time to check the fuel pressures though, something I still intend to do.

I can say that it hasn't been as hot as it was when I was having the problem. Anything with high humidity/heat that would cause a sensor to go crazy? It's been hotter here in GA before and I've never had this happen.

 

[QUOTE=Cyclon36,Sep 3 2008, 08:02 AM] Problem went away since my last post.