Idling Issues

[jwest6601]

The motor got put in the car out of the parts car and ever since it was first started, it's been having idling problems! I changed out the IAC Valve because i thought that's what the problem was but it ended up not being the problem. When it's first started, it idles fine around 800rpms but after about 40 seconds, it'll start dropping to bout 400rpms and rev itself back up continuously. When driving it does the same thing. When your in the gas, it idles fine but when you are going downhill and get out of the gas, the check engine light comes on but when u get back in the gas, it goes off. It's got me lost...anybody got any ideas? The motor is 100% bone stock...

[bonesgt]

If the check engine light is coming on, then get the codes read, could point you in the right direction. Second I would go back and check ALL vacuum lines.

[jwest6601]

I checked all the vacuum lines and to what i could see none had holes in them or were loose. I could get Advance to check the light if it stayed on but they're scan tool only works if it stays on. Our scan tool at work won't hook up to it and idk anybody with one...:thumbsdown1:

[Notch93]

Do it yourself for free.

http://fordfuelinjection.com/?p=13

How did you check for a vacuum leak?

[jwest6601]

I just did a quick check...looked for cracks and holes in the lines. Didn't see anything tho. I'll have to look this link over...thanks Eric!

[capriracer86]

all of ur lines were replaced while it was apart.... we need to check ur tps and see what the voltage is...

[fastoleman]

all of ur lines were replaced while it was apart.... we need to check ur tps and see what the voltage is...

voltmeter set to check dc volts. Black probe to black wire and red probe to green wire.Key switch on (dash lights on-battery,check engine,etc. You should have .98 volts. Set it and start.If it want idle turn the idle screw some and then reset the TPS.It may take a couple of time to get it to where you like. Good luck,Terry

[jwest6601]

voltmeter set to check dc volts. Black probe to black wire and red probe to green wire.Key switch on (dash lights on-battery,check engine,etc. You should have .98 volts. Set it and start.If it want idle turn the idle screw some and then reset the TPS.It may take a couple of time to get it to where you like. Good luck,Terry

Cool...thanks. I'll have to try this out also and see how it goes! I appreciate it!

[fastoleman]

Cool...thanks. I'll have to try this out also and see how it goes! I appreciate it!
No problem...That is why we are here.So all of us can ride....lol...good luck