2001 blazer 4wd Ls
 

Code P0507 it won't pass smog with hi idle I've tried to locate vacuum leak with either and hose,nothing but on the scanner I put it on live data and got this reading,LONGFT1(%) 18.8 LONGFT2(%) 18.0 does those numbers help pinpoint a certain thing for me to look at because I'm running out of patience and time any and all help will be much appreciated

Do you have any other codes or driveability issues? What RPM does your truck idle at? After overnight cold soak, does the truck start at a specific RPM and then slowly settle to a certain RPM or does it just stay at one RPM? How about when the engine is hot and you start it? Does it have a momentary (like split second) flare up and then settle down to a certain RPM or does it just stay at one RPM? Do you have any issues with your brakes, as in do you have to push on them pretty hard before the truck starts braking?

Things you can try:

-If you haven't ever replaced the PCV valve, replace it. They are only a few dollars and should be replaced as a matter of routine maintenance. If it is stuck in the open position it can cause high idle.

-Clean your throttle body. You don't need to remove or disassemble it. Just remove air intake and clean it real well with a rag and some throttle body cleaner or carb cleaner.

It won't start in the morning unless I shoot alittle carb cleaner in the TB I haven't hanged PVC valve but will tomorrow,no issues with brakes idle when cold goes to 1000 then settles bout 845-860 when warmed up it goes up not much then settles but when I turn a/c on it goes from 845 to 1100 to 1000 then to 845 and keeps doing it I've cleaned TB an tpv and had a MAF code come up but then it was gone? I've borrowed a scanner from a friend,a cen tec obd11- abs but don't understand what I'm really looking at hey any help at all would be greatly appreciated .thank you

Have you sprayed a 'carb cleaner' like product in the engine compartment focusing on all vacuum hoses, tbi base, etc. Focus for an idle change while doing..Good luck..Jerry

Read through this thread concerning checking IAC Valve and doing IAC Relearn. Applies to high idle the same as low idle. https://blazerforum.com/forum/2nd-ge...startup-96773/

That long term fuel trim reading would indicate a vacuum leak. What's the IAC reading? If it's closed and the idle is still high, that would support the vacuum leak theory.

Changed PVC valve and vacuum line that ran down to a secondary air pump that's in front of truk pass.side still a high idle as far as AIC reading from live data I'm not sure about that I don't have much knowledge on my scanner I borrowed it without any instructions and couldn't get ohm reading off of aic valve AAHHHH,I've never had such a hard time trying to find/fix anything especially a truck any help on my hi idle issue would be appreciated

Do I understand correctly that you do not get any ohm reading using a DVOM following closely the instructions in the thread I linked (post #3 and post #8)? If you do not get any reading, on the two coils, that would indicate an open internally in the coils and the IAC is valve is not moving and is stuck in one spot. But I don't think that is the case based off the RPM changes you previously listed.

In this post you state you cleaned the "tpv"? Which are you referring to, the Idle Air Control Valve (IAC) or the Throttle Position Sensor (TPS)?

Also,did you do the IAC Relearn posted in the thread I linked (post #5)? There's two versions, try both one at a time.

On your friends scan tool, with the truck running and the scan tool in live data mode, there should be a PID that states "IAC" or "IDLE AIR" or something along that lines. Our IACs work in steps ("counts"), but the scan tool may list it as %. As Tom A stated if the truck is running at idle, and the scan tool shows 0% or any other listing indicating 0. Then there is an air leak somewhere. Also on the scan tool, look at what the Throttle Position percentage is indicating at idle.

I didn't get a ohm reading because of my meter,I have to get another as far as tpv it's tps sensor and I did the relearn it didn't change anything tho I'll do another live Scan and give you the results hey I appreciate be the time you give me on the this more than hen I can say