I just got back from the tuners today and my car is acting up. The car is a 99 Z28. I just installed a comp cams 224/224 581/581 112 lsa cam 1.75 rocker arms, all new valve train, LS6 intake and a TCI SSF 3500 convertor. When I slow down and dont touch the gas or the brakes the car starts chugging at speeds between 35 mph and 50 mph. If I apply the brakes or accelerate it goes away until I slow between those speeds again. Do you think I have a torque convetor problem? Or is it a tuning issue? Has anyone else had this problem? Also I dont think the torque convertor is locking up because the car is using alot of gas and my rpms stay a little high. For example at 75 mph my rpms are at 2300 rpms. Shouldn't the rpms be at or below 2000 at that speed with 3.23 gears? The tuner said the PCM is asking for lock up but I don't think its actually occuring.

Sorry this is so long.

Thanks to anyone with info!
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Anyone?

 

I'd say tuning. Who tuned it?
You do realize that with 1.75 rockers your valve lift is over .600, right? The cam lift is speced out with 1.70s .581/1.70X1.75 Did you check piston to valve clearance?
Converter not locking could be tuning also. With a cam the tuner has to futz with the missfire tables or it won't work right. If the PCM detects to many missfires it'll unlock the 'verter.

 

Al I Pm'd you.