Misfire but PERFECT IDLE, has trouble getting past 2k rpm

[GST Charade]

I just finished putting in new Wisco pistons, now the car is idling perfect, extra smooth but if i give it gas it has trouble getting over 2k, it sputters for about 2 or 3 seconds then its fine fter its past 2k. runs fine from 3k to 7.
My cables are good, changed the plugs 3 times, tps is good, maf is good, timing is fine. i need help!!!

 

[vmason]

did you make sure you have to correct gap for your spark plugs? also how are your injectors and what kind of gas do you use?

 

[92AWDHX40]

Have you done a boost leak test yet, do that frequently because you never know when youll have a leak somewhere, and you just did build .

 

[GST Charade]

I did that this morning, turns out i had a loose intercooler clamp. That was the only problem i could find. I took the car out for a drive soon after and got on the gas on second gear it sputtered for a bit then pulled hard till i let off. Oooh im only running nine pounds of boost right now (breakin) but my cars weighs under a ton.

did you make sure you have to correct gap for your spark plugs? also how are your injectors and what kind of gas do you use?

Yes. My plugs are gapped correctly, i ran two bottles of injector cleaner through them. they are RC sevenfifty cc. Considering the car is idling fine and it doesnt bog under boost i think the fuel is fine.

 

[that_gst]

Id go with doing a boost leak before anything. Check for compression , even though you got new pistons and rings , theres times when compression is low. Of course it can be cause by a ring failure. Improper installation, such as ring marks being downside instead of upside. When you installed your rings, did you make sure the rings were installed correctly ?

 

[TalonFULLtune]

now you guys might think im stupid but I have seen this twice where a mls head gasket wasn't sealed correctly and it had just enough leak at a certain rpm to make the car stutter. but there where no other signs of a leaking head gasket. the plugs didn't eve show a sign really. but all that was done to both cars was a change from mls to oem and the problem went away. just a thought like I said I seen it twice thought I might share. what do you guys think. I would never believe this if I haven't seen it.

 

[GST Charade]

Id go with doing a boost leak before anything. Check for compression , even though you got new pistons and rings , theres times when compression is low. Of course it can be cause by a ring failure. Improper installation, such as ring marks being downside instead of upside. When you installed your rings, did you make sure the rings were installed correctly ?

compression was checked, boost is fine. I had a problem with a loose intercooler clamp but now its ok. my rings are fine.

now you guys might think im stupid but I have seen this twice where a mls head gasket wasn't sealed correctly and it had just enough leak at a certain rpm to make the car stutter. but there where no other signs of a leaking head gasket. the plugs didn't eve show a sign really. but all that was done to both cars was a change from mls to oem and the problem went away. just a thought like I said I seen it twice thought I might share. what do you guys think. I would never believe this if I haven't seen it.

YES! you might be on to something here. Im gonna recheck my cables in the morning because its free and easy. If nothing changes im gonna pull the head off the block and check my Headgsket. Because there is a piece of info i forgot to mention. When I installed the pistons the car ran fine but it wouldnt stop puffing smoke so i pulled the exhaust manifold off and found oil in cylinder number four. I pulled the head off and checked the valve seals and one was bad. I went ahead and changes all my seals and put the head back on. Thats when the problem started. No more smoke just a whole lot of sputtering and misfires. My checklist is down to three CABLES, CRANK SENSOR and HEADGASKET...

 

[TalonFULLtune]

keep us updated.

 

[nismoz]

Mls gaskets are terrible about sealing unless a machinist sends alot of time with the deck and head, I've about got to where I'll use a stock gasket below 500whp cause of this.just not worth the time to pull the head 2-3 times. And rings often seat after a good bit of miles and heat since i doubt they were file fit to the block. May just need a break in...
Arp's n felpro-> the hell with pullin heads cause a $200 gasket wont seal when a $45 one will!

 

[GSR-VR]

Mls gaskets are terrible about sealing unless a machinist sends alot of time with the deck and head, I've about got to where I'll use a stock gasket below 500whp cause of this.just not worth the time to pull the head 2-3 times. And rings often seat after a good bit of miles and heat since i doubt they were file fit to the block. May just need a break in...
Arp's n felpro-> the hell with pullin heads cause a $200 gasket wont seal when a $45 one will!

I've never had a problem with a MLS headgasket. Also I would throw on a MLS and ARP hardware for any build. It's cheap insurance.

 

[vicore]

So often your read and hear about leaking MLS HGs.

Cheap insurance? ^^ MLS costs 50-150$ more and you need the head and block mirror finished.

OEM is a cheap insurance if used with ARPs. Because it seals for sure

 

[GST Charade]

I pulled the head and had it checked and everything looked ok. I checked my cables a few days ago and they are fine. So i went back to my sendors and BINGO... my aif flow meter is acting up. I had my friend give it gas while i placed my hand in front of it and my car reved up like a champ. Im thinking of changing my Greddy Emanage blue for MAFTranslator II.

 

[TalonFULLtune]

if its in your budget get speed density

 

[GST Charade]

Hey guys just wanted give you an update. I bought a used MAF and the car is running fine although i had to adjust the tunning on my greddy ecu. Although the car is running fine I went ahoead and ordered the MAF translator Pro. I can wait.