98 tahoe irregular idle

[Asfalto]

Hi everyone!
this is my first thread here, i'm in italy and here american cars are unknown things..founding this forum makes me hoping to solve my problems!
the car is a 1998 tahoe 5,7 vortec
the problem (very often showing): in D, with the brake pedal pushed, idle is irregular in a continuos revvig between 500/900 rpm; it's annoying at the lights and expecialy when doing some precision move (like park the car in a small space).
thank you for the support!

 

[Phone Man]

Yup had that problem.... surging idle. Clean the MAF sensor first. It measures air flow. Is your check engine light on?

 

[gpracer1]

Check the AIC MOTOR , air idle control.
It may need to be cleaned. This is assuming that everything else is normal and the engine isn't misfiring on a cylinder.

 

[Asfalto]

thank you guys!
the check engine light is off.. but maybe it is burned; should it light on when i turn the dashboard on (and suddenly go off when the engine starts)?
i'm wating for the shop manual to come from the states (it will take 2 weeks), can you tell me where MAF (or MAP) and the AIC MOTOR , air idle control are located?

thanks again!

 

[tahoe.mkIII]

bump

 

[gpracer1]

thank you guys!
the check engine light is off.. but maybe it is burned; should it light on when i turn the dashboard on (and suddenly go off when the engine starts)?
i'm wating for the shop manual to come from the states (it will take 2 weeks), can you tell me where MAF (or MAP) and the AIC MOTOR , air idle control are located?

thanks again!

The MAF is between the air filter box and the throttle body. The AIC is on the throttle body.

 

[Asfalto]

thank you guys!
i'll let you know if the problem goes away.
bye

 

[Asfalto]

I cleaned the MAF with crc maf cleaner but problem persists.
i got the scanner at last, and it reads code p1345: crankshaft position (ckp) - camshaft position (cmp) correlation.
Can it be the cause?
Now I noticed that at cruising speed (like 50 mph), with a very light press on the gas pedal, the engine shakes and it gives no significant power.. I have to add a bit more of pressure to get a real improve of power/speed.

 

[SunlitComet]

uh yeah that is a problem your crank/cam sensor correlation is off and with certain timing and off-ness can cause misfiring.

Can your scanner read live data? specifically CAM_RETARD?

 

[Asfalto]

I bought AutoLink CAN OBDII Code Reader for 50 $ at amazon; it gives a lot of live data and one is SPARK ADV. I don't know if is the same for cam retard.. it reads +20 °.
Anyway I tried to rotate the distributor but that data doesn't change meanwhile the engine started getting worst misfireing so i putted everything back with the previous setting.
problem an code persist!