Hello gang, I'm new to the forum and own a 1998 Windstar 3.8L. I just bought the van thinking it had a bad head gasket. Well, I took the upper and lower intakes off and noticed that there was a bad lower intake gasket that was allowing coolant into the motor. So I replaced that and starting driving it. It seemed to drive fine for awhile; no more coolant was getting into the engine. Then a couple of days later, it started to misfire, mainly at idle. So I checked codes (now please forgive me, there was a code that had something to do with idle malfuntion, but I don't remember it, and it won't come back after I erased the codes.) Still no coolant in system, I think I fixed that part of it.
But it started to idle rough and misfire. I drove it for a couple more days and pulled codes, I got 1451, 0303, 0171, 1538. Spark plug and wire check out ok on cylinder three and the ignition coil had no cracks. I put a timing light on the plug wire and it seemed to fire just fine. I also did a leak down test on cylinder three and it was leaking less than 10 percent.
For 1538, I found that th IMRC was not holding vacuum and wouldn't acuate, so I got one at the salvage that would hold vacuum and installed it.
As far as the 0171 goes, I read that the intake bolt isolators can leak on the 1999 thru 2001. But I didn't know if the same was true for the 1998. So, not having enough extra cash, I put sylicone on them.
Also, the second time I installed the upper intake, I made sure I torqued it down to 89inch lbs and in the proper order in three passes.
When I installed the lower intake the first and only time, I only put sylicone on the corners of the gaskets, I did not put around ports. Number three fuel injector seems to be working fine, I listened and could hear a steady ticking like the rest of them.
Also, I put new pcv valve in, new fuel filter and a new fuel injector kit on cylinder number 3.
Started up, still idles really rough at idle, espicially with the a/c on.
I really need help, this is my wife's vehicle...
thank you in advance

 

171 would indicate vacuum leaks causing lean conditions. Maybe you for got to put a vacuum hose back on?

 

If you care to try this it might help isolate something and that is to switch #3 injector with another cyl and see if the miss moves.

 

Jusr did compression test. It was all good. I took the upper intake off again and swapped injector #3 with injector #6. Does anyone know if putting silicone around the bolt isolators would be helpful instead of new ones? Or maybe someone knows where i can buy a set of the bolt isolator gaskets and not the hole bolt set? Kind of low on cash right now. One more question, would it be possible for me to reuse the lower intake gaskets if i took lower intake off again? I only put gasket maker on corners. How likely would it be that it is leaking? Thanks again guys

 

Mow: I got my gasket set for the '03 Windstar from Advance Auto Parts for about $50. 6 gaskets for the lower intake to spacer (bottom clam shell), 8 grommets and the gasket between the 2 clam shells. Use the Haynes manual for the tightening sequence.

Generally speaking it is not advisable to use plain silicone on the intake or anywhere before the O2 sensors. Silicone will coat the sensors and they are done. Use only o2 sensor proof gasket makers.

 

The 1998 model is a little different, I think. The upper intake is only one piece and has twelve bolts and isolators. I can't even find a set of them, all I can find is a set of the bolt isolator grommets, not the bolts themselves - part number f68z9s479a, $6.99 each. I can't find a intake manifold set that comes with the grommets. I guess I will have to buy the grommets for $90 -- seems rediculous for some rubber pieces, but that's life, i guess.
thanks for the tips on the silicone.

Is it possible for a leak in one of these bolt isolators to cause a misfire? Or would a leak there just be causing the 0171 or 0174 codes, not the misfire? Anyone know?

 

Yes it is different. Did you try RockAuto.com ?
You could also compare the grommets for the later models with your old ones. If you are lucky they fit.

A lean condition can lead to missfires. If the leak is where the #3 runner is located it could cause a particular lean condition for that cylinder.

 

I too own a 98 windstar with a 3.8.I was having the same codes for imrc. I took off the upper manifold plenum and cleaned the ports and butterflies.When i replaced the upper manifold plenum on a 98 3.8 is it necessary to replace the black grommets with green ones? I have heard it both ways. Also does the plenum have to be torqued to the specific amount of inches or foot lbs? The reason i asked is i put everything back together and now my engine wont start. Battery is strong.It was running great,except for not idling good. Thanks for any ideas.I think everything is hooked up ok.