Calling all 996 gurus! Problem with lack of power

Hello all! I need your wisdom and guidance please! Calling all 996 gurus! Bought a long block from a reputable guy so far it�s treating me well🤘. This is my second 996 that I have owned. Both were tips. My last was high mileage but pulled hard. This one so far seems to hesitate around 3k rpm and just seems to lack power and pull. just exhaust noise but no go. So a couple things I was thinking maybe it�s the bolt on upgrades. However I don�t think they gave the guy the same issues so not sure. I have a evoms air intake and changed it back to stock thinking that was the issue. I have a aftermarket exhaust system from fabspeed and fvd with muffler delete pipes. So I cleaned that maf on the stock air filter but still no change. Then thinking maybe it�s the aftermarket exhaust. So I could switch back to my factory ones if need be. Not sure what to think. If you have ideas that would help. Ireplaced the MAF and fuel pump. Still not better. I�m stumped and very discouraged! 😢 Ideas would be helpful. 🙏🙏🙏🙏

Maybe tell us which of the 2 996 engines u have and some info about it....year,, milage any recent work to it

Thanks!! Sorry here you go!! I have a 996.1. Replaced the engine this summer with a rebuilt engine. 9k miles on rebuilt engine 128k on body

Compression test, if that does not have alarming results, leak down test. What fuel are you running ? Where are you getting it ? Power always consistent regardless of station you use to fill up ? Are you running cat's ? Any DTC's ?

About that 3k rpm the variocams kick in. Do u have a scanner that can read the cam deviations (a smoothed value that will stay constant)and actual cam values (will change with rpm). Any chance u can get a fuel pressure guage on the rail and read it under load. Would be nice to rule out fuel delivery. Lastly tell us about the rebuild.....basic rebuilt, bore increase, upgraded parts, nicki coatings, aluminum or steel sleeves? The more u give us the more we can help.

here�s the rebuild invoice. Have not done a compression test since I installed it

So this topic went from power loss at 3K rpm to you having an $8K quote. Seems an extreme jump from one to the other. Mind telling us how you ended up here?

The previous guy asked what was done on the engine rebuild. Easier for me to just show the invoice 🙂

I would go with previous suggestions and do a compression and leak down test before throwing more parts at it. Throwing unnecessary parts at a Honda or Toyota can get expensive, a Porsche will get expensive even faster! Did you have low fuel pressure or an issue that indicated you needed to replace the MAF & fuel pump? Do you have access to a quality scanner or scope?

Quotes source post: 19742825

Triple this suggestion. For all we know it could just be that the throttle body needs to be recalibrated. In case you don't know: Use a scan tool to erase any trouble codes Turn the ignition switch on without cranking the engine for about 45 seconds; listen for audible clicking and then a buzz. Turn the ignition off Start the vehicle and verify that the accelerator pedal works correctly and the vehicle accelerates normall Once the engine has warmed up let her rip and see what happens. Check for codes. Assumption:You have a code reader You prefer to wrench on your own car You know enough to get yourself into trouble. Otherwise, find a friend that does. Good luck!

So based in that rebuild it looks like they reused the original pistons and rings. The issue with these motors is that the cylinders "oval" over time and because of that u have to reuse those parts if u dont machine the bottom end. When u reuse those parts its very hard to get it all back together in exactly the same orientation..... I think your next step is a compresson check to verify the health of the rebuild. I wish i had better news, hope the numbers come back good.

Thank you so much for everyone�s input! My friend is a mechanic and we�ve owned to do a compression test this week and also check the codes and scanning to see the throttle body issue 👍🙏 i will let you all know what we find out!!

Any time I have an issue with not having full power at full throttle, I always test the fuel pressure under full load first... I use a manual fuel pressure gauge with an 8ft long 1/16th hose ran out from under the rear lid, over the top and taped to the windshield so I can drive it at full throttle and watch for fuel pressure drop... Of course if you have a chassis dnyo handy...a long hose on the fuel pressure gauge is not necessary, just the short one that comes with the gauge is all you need... IF you have full fuel pressure, and good compression, then look for blockage in air filter or anywhere in intake system or exhaust system like catalytic converters... Lastly check cam timing and ignition timing... I had a GT3 one time with lack of power that had been to 3 Porsche Shops and was put on the Dyno to verify low power( still in Porsche Warranty)......It came to me as a last resort before getting a new engine. After verifying all the necessary fuel, air, compression ect.. I hooked up an "Old School" timing light and found the Digital Ignition Timing was off by 25 *....( lessen here is don't trust what the computer says the timing is...actually check this is what it is says it is)...I Pulled the Trans and flywheel and found the timing ring on the flywheel had slipped by 25*.....I still have the pic of the flywheel if I can find it ill post it...