andy9743

hey guys. i'm getting some surging that almost feels like a miss at crusing rpm's. car is a 99 frc c5 with halltech intake, ls6 intake manifold, cnc ported heads and a small comp cam. all work was performed by mike norris and tuned by mike. about 500 or so miles ago the work was performed and the surging just started today. i checked all the cai connections a few were loose but not enough that i would suspect unmetered air would get in. tightened them up and sprayed the connections with carb clean with no change in the idle. new plugs, wires and fuel filter at the same time as the other work. car pulls strong still and idles fine.

i would take it back for mike to take a look at but im in NW ohio and he's in indy. thought i'd poke around myself first hoping its something easy.

any ideas?

andy9743

any ideas guys?

diablotruck

iTrader: (25)

check all connections on the intake for unmetered air. any codes set? check all connections (plug wires, coils, injectors) could be a bunch of things. hope that helps you.

andy9743

no codes. i checked the cai for unmetered air all connections tight, going to check that actual manifold to be sure it didnt loosen up. tuner suggested swapping plugs.

pauls99z28

iTrader: (32)

fuel pump could be going out. Had that happen to me. Just a thought.

andy9743

car does have a few miles on it, but it only does it when cruising. not when accelerating or at idle? idk if that makes sense?

D14HUGGER.ORANGE

Maybe o2 sensor could be getting close to fouling out. If your cars running rich it doesn't take long for them to foul. I fouled out my o2 sensors last week and it caused surge almost too stalling out.

pauls99z28

iTrader: (32)

I understand. What you described i experienced. Under load pulls good and good idle but when cruising at certain lower rpms i'd get surge until i give it more gas then surge goes away. After a month of that went to start her up and wouldn't start...ended up fuel pump was done. Like i said..just a thought. Hope that helps.

andy9743

o2's were replaced when the cam was done but possible to. thanks for the ideas guys.

D14HUGGER.ORANGE

Oh ok never mind surge is at 1000k and up not idle

mkvamso

iTrader: (2)

Sounds like 02s
My car did the same thing around 2k or so, seemed like a misfire
If i gave it more throttle it would clear up, and it didnt do it at idle.

I drove it around that way for a few days until it threw a code for 02s not switching enough in a certain amount of time.
Swap em out and see if it helps, your tune might be rich causing them to die prematurely,