Hesitation and cut out

[zjustin28]

So, when trying to accelerate (not even under boost) my car gets very jerky. Like its loading up. Feels liek the motor is being put under load. ANother example of this is when brake boosting, once full boost is built, it feels like it slightly cuts in and out. Not fuel cut, just a slight jerkiness.

Tonight, i was driving along, and it started doign it slightly. i ran a WOT pull in 3rd to see wtf was going on, and it was shuddering/jerking the whole time, then, around 5500 rpm, it cut out (nto fuel cut, like the car mis fired) and now the problem is gone. Ive done this before, and in a day or two it comes back.

Mod list:
FMIC, MBC (only @ 13lbs), full exhaust, 02 dump. I just recently did NGK Plug wires, and bpr6es. I did bpr6es (gapped at 25) before the fmic, exhaust and mbc. Wondering if going to a colder plug may help?

 

[RoryBarron]

Have you done a BLT yet? Like this. Sounds like you have at least one, and that will cause the symptoms you are describing. The plugs are likely not the issue since they are new. The usual gap is .028 though.

 

[Boostinsideways]

Run a boost leak test, if that shows good then try to narrow your plug gap a small amount. You might (probably aren't) getting plug blow out.

If you have not rewired your fuel pump, now might be the time.

 

[zjustin28]

would a blt be like this though? comes and goes? thought that a boost leak would be an always type of thing.

 

[RoryBarron]

would a blt be like this though? comes and goes? thought that a boost leak would be an always type of thing.

It's very possible yes. Depending on where the leak is, it could be when it is warmed up and the rubber of the piping/couplers are more pliable. Either way, you should do it for peace of mind. Even if that isn't the issue I promise when you get em all fixed you will notice a difference in the butt dyno.

 

[guseclipse]

Do you get a code (misfire?). I started getting this code when my head gasket started to go and it studered sometimes. Ran fine under WOT.

 

[zjustin28]

Nah, never had a cel pop up.

Ill get around to doing a BLT here soon then. Not too sure thatll solve it, as i just did one a month ago and everything was peachy. Any other suggestions?