Hi i bought the for 1400 bucks with 275k miles it had a bad power loss problem so i had it put in the shop they said it was a bad head that 2 and 4 was'nt fireing so i bought a refab head and had them put it on well chargeing me $780 it run better but still something else was wrong cause it will take off like normal then all sudden just fall and lose's a bunch of HP so i took it back to the shop and they stuck a crank sensor on it and replaced the Cat and charged me $360 and i got it back and still did'nt fix crap same problem as before and they test drove it and acted like it was a 4 cly auto and thats all the power it would get so i said screw it i wasnt paying them any more money not to fix the problem so now im left trying to fix it my self which is what i should had did in the first place.

So heres a break down of whats been changed its a 4cly 2wd 4runner

refurb Head
plugs
plugwires
coil pack
cat converter
crank sensor
and i swap MAF's out and didnt fix so i took the new MAf back for a refund.

I dout its a mechanical problem im thinking its something electrical cause like if its cold i can start the 4runner and drive just fine for a few mins then something stals and holds it back. And sum times i can stop at stop sign then it will take off real fast then all sudden just fall's So do u guys have any idea what it could be?