idle problem=vacuum leak maybe??

[stangthing150]

My 1990 3.0 5spd has been idling at 3500. I replaced the tps and that didn't help, and now when i step on the brake the idle goes way down and pulses up and down. Im thinking vacuum leak? not sure where it would though be any suggestions? Or could it be a leak after the maf in my air intake? there is also a check engine light on but i haven't had it scanned yet any help would be greatly appreciated.

 

[Bad_Vision]

vacuum leak buddy you answered your own question with the brake pedal. the brake booster draws straight from the intake pressure, if you have never replaced the vacuum lines then you might as well if you want to make the engine look good you can get some silicon hose in many colors to spruce up the engine bay. if you don't want colors just get some vacuum lines its cheap to buy it by the foot.

also just for reference you can test the TPS and MAF to see if the are working properly before you buy those costly parts.

 

[stangthing150]

ok thank you i started replacing the lines so i guess ill finish doing that

 

[stangthing150]

I have changed most all the lines at this point. As I drive it the idle hangs around 1500-1700 then the longer I drive it the idle starts climbing to 2200-2500. Its no longer pulsating unless I twist the tps to get the idle around 1000rpm. Whats stock idle normally?

 

[Bad_Vision]

850???

 

[stangthing150]

need some help on a vacuum line. it runs from the throttle body to an steel line by the firewall and intake manifold, then out of said line to a "T" one of which goes to the black canister. Where does the other go? I was completely missing that line.