hello all, long time lurker first time poster here;
1998 GMC Yukon SLE 4x4; 5.7, 4l60e, 10bolt rear
TLDR:
truck shows 2 codes p0740; TCC solenoid, and p0452; FTPS low voltage.
recently did a mild engine refresh with a few performance parts, and a Blackbear tune, the truck feels really sluggish and boggs down while accelerating over 2000RPM. If I unplug the MAF the truck runs perfectly, smooth, and fast.
The truck shifts great through all gears just fine, I honestly have no idea where to start diagnosing this thing, I've ordered the ftps it'll get here in a few days, but I don't think its the root cause.
Longer version:
a couple of months ago, the head gasket started leaking so I bit the bullet, tore down the engine, and rebuilt it with a 395 cam, Chevy performance valve springs, spider injectors, and full felpro gaskets and bolts. after the rebuild the car felt really sluggish but had no check engine lights, got the blackbear tune, and the issue persisted, but I got a check engine light. checked it out using a clone tech2 and got 2 codes, p0740 and p0452, tcc solenoid, and ftps low voltage. I checked the ftps voltage it reads 0v and I'm currently waiting for one that I've ordered. for the tcc solenoid, I have no idea how to go about chasing the problem, the trans runs great so I'm guessing it's just a wiring issue? what completely throws me off is that I accidentally disconnected the MAF and the truck ran spectacularly except for the hard shifts, when I plug it back in , the car goes back to feeling insanely sluggish and boggs down post 2k rpm. if you've had any experience with any similar issue your input would greatly be appreciated.
1998 GMC Yukon SLE 4x4; 5.7, 4l60e, 10bolt rear
TLDR:
truck shows 2 codes p0740; TCC solenoid, and p0452; FTPS low voltage.
recently did a mild engine refresh with a few performance parts, and a Blackbear tune, the truck feels really sluggish and boggs down while accelerating over 2000RPM. If I unplug the MAF the truck runs perfectly, smooth, and fast.
The truck shifts great through all gears just fine, I honestly have no idea where to start diagnosing this thing, I've ordered the ftps it'll get here in a few days, but I don't think its the root cause.
Longer version:
a couple of months ago, the head gasket started leaking so I bit the bullet, tore down the engine, and rebuilt it with a 395 cam, Chevy performance valve springs, spider injectors, and full felpro gaskets and bolts. after the rebuild the car felt really sluggish but had no check engine lights, got the blackbear tune, and the issue persisted, but I got a check engine light. checked it out using a clone tech2 and got 2 codes, p0740 and p0452, tcc solenoid, and ftps low voltage. I checked the ftps voltage it reads 0v and I'm currently waiting for one that I've ordered. for the tcc solenoid, I have no idea how to go about chasing the problem, the trans runs great so I'm guessing it's just a wiring issue? what completely throws me off is that I accidentally disconnected the MAF and the truck ran spectacularly except for the hard shifts, when I plug it back in , the car goes back to feeling insanely sluggish and boggs down post 2k rpm. if you've had any experience with any similar issue your input would greatly be appreciated.
