1998 Windstar P0171 & P0174 Codes

I'm trying to get rid of these 171/174 codes to pass emissions.

Recently I did the temporary fix for the IMRCs and got rid of those codes. While I was at it I cleaned out the intake manifolds and egr ports, replaced the upper and lower intake, IAC and throttle body gaskets. All four HOTS are relatively new, a few months old at most.

The only other problems I know of (I've replaced just about everything I could in this car) is the A/C controller doesn't work and I am guessing this is a vacuum leak somewhere, and the cruise control doesn't work.

Could the vacuum leak causing the A/C problem be causing the 171/174 codes?

Is there anything else I need to check?

:banghead:

Oh! There's one other problem... there's a very slow brake fluid leak coming from the part just below the fluid resevior, could that have anything to do with it?

Your cruise control does not work because of the leaking switch at the bottom of your brake fluid reservoir. IIRC, the part is only about $20 and will take you 5 minutes to change.

On 99's and up, the codes are usually caused by the bad isolator bolts. I do not know if your 98 is caused by the same. Maybe someone else will chime in. In the meantime, keep looking for vacuum leaks.

Thanks, I never would have guessed the brake leak was even related.

The intake manifold design changed in '99 (due to cosmetic front end changes), which caused the isolator bolt problems in '99 and up 3.8L Windstars.

So the problem is likely a vacuum leak. I had the same codes on my '98, and it turned out to be the IMRC actuator.

Since you know that there is a vacuum leak affecting the A/C controller, plug the line (or better yet, find the leak) and re-check the codes. Process of elimination will get you there.

The intake manifold design changed in '99 (due to cosmetic front end changes), which caused the isolator bolt problems in '99 and up 3.8L Windstars.

So the problem is likely a vacuum leak. I had the same codes on my '98, and it turned out to be the IMRC actuator.

Since you know that there is a vacuum leak affecting the A/C controller, plug the line (or better yet, find the leak) and re-check the codes. Process of elimination will get you there.

Thanks for the tip, I guess the easiest thing would be to plug the lines at the A/C controller. I just started a new job and don't have the money to do all the permanent repairs until next payday, I just want to pass emissions.

I got a ticket this morning. :nono:

Anyone know exactly how far you need to drive and how many on/off cycles you need to ensure the SES light is off?

I guess the 0171/0174 codes will come back right away, before the SES light comes back on, if that isn't the cause, correct?