ill try to make it short-94 chevy 2 c1500 4l60,350 with sd tpi,i built this motor a year ago,206 212 comp roller,9.25 comp,mid lenght headers,i thought a tpi would be an excellent idea and did some checking around and put it on using the trucks ecm with by splitting the injector harrness,had chip burned by a reputable place tha claim to have done this and it worked out okay,so 300 later it ran great! monster tourqe good drivable power,etc,there was some surge on decel and a little hunting at idle but no big deal,i was warned about this poss already.3 months later it got worse,.then stalling , then constantly stalling on decel or quick stops,right away i noticed it was going lean at idle and it was cranking the fuel trims to 165 while trying to idle,then it would be fine,until you changed gears, or accelerated or any thing that would reset the fuel trims it always stalls froom park to reverse,{resets the trims}.every thing else was great. since it ran well up untill now,i assumed sompthing went bad to cause this,but i cant find any thing wrong,every sensor reads fine ,wires test good , good grounds over the last 6 months i have changed every sensor but the o2 witch works great, with known good parts, including the distributor . no vacum leaks,fuel press. good, etc.i even tried an ecm fearin injector driver mods. now heres the fun part, i decided that the only thing left was to get the chip fattenend up at idle, made no real difference,i decided to look around and was pointed to fast electronics,as they ve had succes with this setup and assured me it could work if i went to 19 lb injectors and they burned a chip to match.it worked for about a week only after i set the tps to 70 other than that its back to the same old stalling and hunting,o2 is in the teens and 0oo on decel and idle,until the block learn hits 160,unfortunatly it takes to long to figure this out and usually stalls [reseting the trims also]upon start up it hunts then stabl izes and then you can start all over again.i have changed the iac using a tbi style before the last chip are they really different? IT DIDNT seem to change any thing and the counts vary fro 80 TO 120 SO its not like its trying to close all the way open loop,pe, and cruise are right on,128.the engine is fresh and sound,runs strong,feul press and timing adjustments dont seem to cure this lean spot,as it always learns around it,im at my last straw if i didnt have so much time and money invested in chips i would piggy in my 737 ecm,but itll be back to more adaptors chips etc. and i fear im going to run into the same thing,and im just missing sompthing any ideas please!!!!!! thanks

 

Is the VSS hooked up correctly and working?
No VSS ECM does not know you are decell......

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http://www.thirdgen.org/techboard/tp...v-truck-w.html