VX SS 5.7L High Idle on cold start only 1.9k to 2.0k rpm !!

[Demonrt8]

Cold start with high idle where the problem is parameters ..

 

[Demonrt8]

Cold start when the engine skips the high idle and starts to jerk stalls at very low idle

 

[Demonrt8]

2500 RPM ( LTFT ) Parameters

 

[Demonrt8]

Btw i recently changed the whole fuel delivery system parts by a new sets and parts ( new complete fuel pump , new fuel filter , cleaned the whole 8 injectors and tested them before installing them back , fresh iridium spark plugs , new s.plugs wire set ) etc. so i think my fuel delivery is ok … i don’t know it :/

 

[07GTS]

looks you have a large vacuum leak somewhere
long term fuel trims almost maxed out and MAF reading low
did you check LTFT at 2500rpm
edit= just noticed one screen shows maf low and one shows maf correct
need the 2500 rpm to determine if vac leak or fuel delivery problem

yea thinking looks like air leak somewhere too, idle spark goes down to 4 deg and tps to zero shows it's trying to lower idle rpm but there is too much air

 

[Demonrt8]

yea thinking looks like air leak somewhere too, idle spark goes down to 4 deg and tps to zero shows it's trying to lower idle rpm but there is too much air

Should i replace the MAF or IAC again by a different part number iac .. could the problem be there ?
Since the last 2 iac’s i changed was the old iac part number for 98-99 5.3’s 5.7’s
Or should i re-check on vacuum lines again + manifold gasket ?!

 

[07GTS]

if u can look at the iac counts that will show u if its all way closed or open which will also give an idea of whats going on, if its all way closed then its external air getting in somewhere, maf only reads air volume dosnt control it, check everything plastic or with a connection to it and hoses ect for any splits or anything

 

[lout]

where did these fuel system parts come from
i am concerned about the high fuel trims at 2500rpm
looks like you have a vacuum leak
and weak fuel delivery or incorrect injectors

 

[Demonrt8]

where did these fuel system parts come from
i am concerned about the high fuel trims at 2500rpm
looks like you have a vacuum leak
and weak fuel delivery or incorrect injectors

I will re-check for vacuum leaks , but for the fuel delivery all oem parts from acdelco or high end aem parts injectors are factory oem though recently checked and ultra sonic cleaned so .. i think i will start with tracing vacuum leaks first

 

[lout]

what fuel are you using
if ethanol could account for high fuel trims