power loss from 3k to 5k rpms

[Exar-Kun]

hey, heres the scoop, if anyone has any ideas, It would be most helpfull..

I got my head redone recently, and isntalled, timing set, new gaskets and such..

I noticed afterwardS(after the 500mi break in) that my power was kind of "lagging" from 3k to 5k rpms..so I took it into the dyno, and sure enough, from 3200 to 5k or 5200rpm theres a 15-20hp drop in power, then it kicks back up like crazy...

I dont have aftermarket cams, so this seems odd. I pulled the plugs, they look fine, jeff tyrell checked the timing and it was set a 18deg so we reset it to 15deg(where it is supposed to be, right?) and tried again...no rela results to speak of.

So, here the deal, jeff pulled the valve cover off and checked the timing chain/cams, no slipped tooth, etc...and the timing is still dead on. ANyone have any ideas? I' thinking a fuel injector or something is being a pain or possibly has an odd leak.

I do, on occasion smell a little faint bit of gas in the mornings from the engine bay, which leads me to think an o-ring may be damaged...anyone have any inputon where to start?-chet

[Nismo_Freak]

KA timing should be set at 20 degs. at idle.

Run a wideband test and you'll know why it's not making the power.

[Exar-Kun]

we ran a wideband 02 during the dyno, the a/f ratio was right after tuning, and its still had power loss, with no AFC tuning the a/f ratio was very lean, like 15-1....Jeff is going to see if theres any leaks in the intake gaskets, etc then check out the injectors and things, the ECU didnt throw out any codes in the consult reader(ecu codes, etc) and didnt show the knock sensor going of during runs around town even when it got warmer..-chet

[NISTECH]

Is the egr hanging open? Check your TPS setting?

[Exar-Kun]

TPS and EGR were fine, so was the fuel injectors, etc...it was a bad knock sensor, and at 3-5k it would retard the timing severely, so we wired around it for now, I got a new one on order...anyone got a good deal on a OE knock sensor?-chet

[JONBOYRACING]

how much you want to pay i may find a good deal on one in the ATL area....

[Exar-Kun]

100 dollars..NEW.-chet