I've had my car since December and it cuts fuel sometimes, seemingly random. First times happened on highway, so I figured maybe it was heatsoak from stop and go traffic. However, it has continued happening since then. On the street, I've noticed it when doing a slight left hand turn and getting on it (it goes through the turn but then cuts when going straight). Yesterday I autocrossed the car for the first time and was absolutely killed by this. At the suggestion of another driver, I went and filled the car up to over half full and that made no difference at all. Most of this was after doing left turns (a 180 around a single cone, so fairly sharp, and then a long steady left hand sweeper). I have power going through the turns though, but when the car straightens back out and starts going forward, fuel cut and the car falls on its face.

I tried whacking the MAP at the autocross yesterday twice to no avail. Where do I go to next? I've read some replace the MAP, some replace the fuel pump, some have changed spark plugs. . .

Any ideas? I need a solution before the next autocross in two weeks or else it wont be much fun either. Also, I have to adjust my throttle cable, but I don't think that would be the cause of this (ie the cable getting stuck or something because of extra slack). What does everyone think?

 

Did this again last night when I was driving. Taking a left in a fairly large interesection (so not a hard turn), I got on it in first, took it to redline (was not turning at this point, just going straight after making the turn), shifted into second, got a split second of power after shifting and getting back on the gas, then fuel cut until I let off gas for a bit.

It only does this when I get on the car hard. During normal driving around town, out of Vtec and shifting around 4500rpm or lower, no problems.

 

To report back on my problems. They continue, but not as much. After the last autocross, I took out all the slack on my throttle cable (probably not related, but still a good thing to do).

At the autocross I was at yesterday, we all got 4 runs (2 in the morning, 2 in the afternoon). Tank was at 1/2 full, car fully warmed up, air temps in the 40's, maybe low 50's. First runs in morning and afternoon sessions went fine. Second runs though, it cut the fuel on me right around 4-5k rpm. Did this right after a slow, tight left handed "traffic circle" kind of element (think of a circle, enter it on the left hand side, go around bottom, back up around top, and then exit at the bottom again, so around 450 degrees).

Why would the car behave different on the first run as opposed to the second (runs were probably 10-15 minutes apart). Would lead me to believe the MAP sensor and fuel is not the problem. What else can I look for?

 

Any CELs? Run a bottle of high quality cleaner in the gas tank, I use Techron. Have you checked your oil level lately?

EDIT: Also, try physically removing the MAP sensor and cleaning the pins. The map whack procedure is halfway effective for most people because it just happens to reset the connection with the MAP pins. Remove the whole thing and clean all the connections, see if the symptoms go away.

 

No CEL's, ran Techron in tank less than a month ago, changed oil to Mobil 1 synthetic about a month ago and level has been at the top of the dipstick since (I check about once a week).

Have not yet removed the MAP to clean it that way. I will definately try it before the next autocross though as getting the car to behave this way on the street is very hit or miss. After I adjusted the throttle cable, I did the same left hand turn as in my second post and didnt have any problems with the fuel cut. Thanks for the response.

 

So nice to see someone on here that's competent with their car and knows how to go through the necessary troubleshooting steps.

After removing the map and cleaning the connections, if the problem still exists then I'm running out of ideas. If this problem were related to spark plugs then you'd think the car would have the symptom all the time and not just when running hard on the track.

I suppose it could be the fuel pump, just like you mentioned previously. But I have no idea what the symptoms of a bad fuel pump are. Maybe a more experienced member could give more input. You might try heading over to s2kca and asking Xviper about your situation. He always seems to have good suggestions for these hard to troubleshoot problems.

 

Personally

I would hook up a fuel pressure gauge, and watch for a pressure drop when the car acts up. This is all based on your description.

 

Back from the dead (of just over a month). Had an autocross two days ago and the car had no problems like before. I did various things and apparently one of them did the trick.

1) Took the MAP sensor off of the car, made sure it was all clean and put it back on.
2) Ran on more or less a full tank (less than 40 miles since fill up)
3) Ran the AC hard for about 3 minutes right up until I was on the starting line

I can't tell you how great it was to NOT have a problem with the car. Hopefully it won't experience these problems anymore. Thanks for the suggestions from everyone.

 

I have and still continue to have this problem... Ive done the map sensor wack and still same problem. Only on left hand turns as well, I have noticed the issue is not as prominent with more than half a tank. I am suspecting maybe a dirty fuel pump sock, dirty tank or fuel pump going bad could be the culprit. CobraTi, keep me informed if you continue to have issues please.