Heres the situation. The car is a 2000 gtp. Mods are in my sig, but I will list them. XP, new wbs ic, togs, stage 4 m90, STOCK tb and maf, among other tid-bits. When I start the car when it is cold, is runs fine. It doesn't act up until the car is at operating temp (drilled 160 stat), and you shut it off, and restart within an hour or so. When i start it, it will cough and stutter, like it has a HUGE vacum leak, the same thing it would do when you pull the vacum boost line off while it's running. It will then come out of it, and idle fine, the do it again about two more times, and then it will run like a champ until you shut it off, and restart.
I have checked, and check, and triple checked for any vacum leaks, including at the ic, s/c, tb, fuel injectors, evap system, and anywhere else I could think of. I do not think it is a vacum leak issue. The ltft idles around +10-14, and stays around 0 when the TP% is increased. The IAC's are steady at 58-60, but when the car acts up, it jumps to 100-110, and then drops back down when it comes out of it.
I took the purge solenoid off today to see if it was leaking/stuck/inop, and with the off and the lines capped, it still did it. When i went to reset the SES light, i noticed it had a MAF code as well. it was a history code, i believe it was a p0101 which is a genaric code for performance. so i unplugged the maf when it was acting up, and it came out of it very quickly, and was fine. now i understand it's just going into open loop...so here is my conclusion:
After checking for B+, ground and a 5v reference (which are all good, no resistance), so it is either in the tuning (not sure what to look for in the maf tables) or the maf sensor is bad. I dont have a spare maf, so i am trying to source a cheap one to see if it is indeed the problem. I find it hard to believe though that this just 'went out' for two reasons, one, it didnt do it before the i/c was re-installed and the car was tuned (which i am confident neither of which are the issues), and two the maf reads correct hz, and g/s while it is acting up.
Does anyone have ANY suggestions on what else to try? I'm stumped.
CLIFF NOTES: car has a bad sputter/cough upon start up at operating temps~
I have checked, and check, and triple checked for any vacum leaks, including at the ic, s/c, tb, fuel injectors, evap system, and anywhere else I could think of. I do not think it is a vacum leak issue. The ltft idles around +10-14, and stays around 0 when the TP% is increased. The IAC's are steady at 58-60, but when the car acts up, it jumps to 100-110, and then drops back down when it comes out of it.
I took the purge solenoid off today to see if it was leaking/stuck/inop, and with the off and the lines capped, it still did it. When i went to reset the SES light, i noticed it had a MAF code as well. it was a history code, i believe it was a p0101 which is a genaric code for performance. so i unplugged the maf when it was acting up, and it came out of it very quickly, and was fine. now i understand it's just going into open loop...so here is my conclusion:
After checking for B+, ground and a 5v reference (which are all good, no resistance), so it is either in the tuning (not sure what to look for in the maf tables) or the maf sensor is bad. I dont have a spare maf, so i am trying to source a cheap one to see if it is indeed the problem. I find it hard to believe though that this just 'went out' for two reasons, one, it didnt do it before the i/c was re-installed and the car was tuned (which i am confident neither of which are the issues), and two the maf reads correct hz, and g/s while it is acting up.
Does anyone have ANY suggestions on what else to try? I'm stumped.
CLIFF NOTES: car has a bad sputter/cough upon start up at operating temps~