I have a problem with violent jerking with my car when I'm cruising and the car is under vacuum. The problem is intermittent and mainly happens when I'm driving long distance 90+ miles or so, or when I'm driving the car really hard under boost and as soon as it under vacuum a little after boosting, the car would jerk violently and uncontrollably.

Mods: Built and sleeved LS engine, Bosch 550 cc injectors, t3/t4 turbo, intercooler, AEM fuel rail, upgraded fuel lines, SARD fpr, Tial wastegate, cam gears, 3.00" exhaust, Bosch intank fuel pump, MSD 6AL, MSD blaster 2 coil, Hondata 2B, 3 BAR map sensor, Apexi AVC-R....

Fuel, electrical or ignition problem?

 

i know someone has experience the same, or a problem very similar.

 

does it happen right after you let off the throttle? I had the same problem and it turned out to be a boost leak. Check for leaks, it cant hurt and odds are that you have a few, even if that isnt the problem.

 

how would i check for boost leaks? also, it happens when i run the car extremely hard or during long distance trips at cruise the whole trip.

 

a boost leak will not cause a violent jerking like you described. What fuel management are you using?


Rob

 

okay sorry you have hondata, its probably in your tune. Ar you running lean when it happens?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rjardy &raquo;</TD></TR><TR><TD CLASS="quote">okay sorry you have hondata, its probably in your tune. Ar you running lean when it happens?</TD></TR></TABLE>

unfortunately, I don't have a wideband in the car and don't know if it is leaning out. hopefully, that isn't the case.

i believe the problem could be caused by these parts (feel free to correct me if i'm wrong):

-distributor

-3 BAR map sensor

-MSD external coil

-MSD 6AL

-ignitor

-injectors

-fuel pump

-FPR

 

i was having the same problem and ran a diagnostics for the check engine light.. Turned up being an 02 senser problem. I looked under the car and found that one of my sensor wires was ripped in half, so i twisted it together and it fixed the problem

 

that is the thing that is frustrating, no CEL at all.

 

My guess is definitely O2 sensor problem. I had a similar problem, only surfaced after long trips. Turned out the longterm fuel correction factors has changed to a point that the car was running so lean it was misfiring. Fixed the O2 sensor problem and never had an issue since.

 

is there a way i can test the 02 to see if it is actually the culprit before i fork out the $180-200 for the sensor?

thanks

 

annnnnybooooody??