Engine Miss 1996 3.8L

My 1996 3.8L With 140K miles developed a very slight miss.
The problem gradually got worse until the check engine light came on every time I went out (after reseting it).
I had already cleaned the EGR ports and changed the spark plugs with O.E. Motorcraft double plats.

I replaced the plug wires and coil pack, and also replaced the camshaft position sensor.

I cleaned the MAF sensor.

I verified proper operation of the IMRC.

I found that the EGR valve was getting vacuum at idle.....and that the EGR valve was sticking slightly when I manually gave it vacuum through a tube. I corrected the constant vacuum by spraying a little SeaFoam into the vacuum line for the EGR valve.... Then I replaced the EGR valve, DPFE sensor, and the EGR vacuum regulator solonoid.
Rechecked the EGR ports.... Still clear.

I replaced the upper intake manifold gaskets, and checked things over for a vacuum leak.....no change.

Still had the miss.....and getting worse....
At the point that the Check engine light came on consistantly....
I had the codes read at Autozone.....Missfire on Cyl. 1. No other codes.
I switched the spark plugs between cyl. 1 and 2. The spark plug for cyl 1 was the cleanest in the engine....
Cleared the codes....went for a drive....and when the engine light came on, I had Autozone read the codes again.....same code, missfire on cyl 1


I bought a new fuel injector. And I cleaned the other 5 injectors.
LOTS of crud in the injectors....in spite of using fuel injector cleaner.
True....the injector I replaced is likely good....but I was tired of taking that upper manifold off so many times.....so I wanted to be sure.
Car runs MUCH better.

As a note to add to the injector service process.....
After I reassembled the fuel injectors and rails.....
I turned the key to the "ON" position to activate the fuel pump and then turned it OFF.....checked for leaks.
Then I released the fuel pressure release (middle of the front fuel rail)....
releasing air.... Then I turned the Key ON again....then OFF....and checked for leaks again.....released the pressure again.....fuel came out.
I did the ON / OFF a 3rd time..... and waited 5 minutes......then released the pressure again.... This process made sure that there were no slow leaks.....as the system maintained pressure.
I did this with the upper intake manifold off.....as I would not be able to see any leaks on the back cyl. with it on. And....you can make any needed repairs at this time.


From reading several forums, this is a difficult problem to resolve...
And in my case.... I would think that the EGR and the injector crud were both causes of my problem....and maybe this will help someone else.

Update,
I am told that a buildup of crud in the injector cup is normal with many miles....even with good gasoline and ocassional fuel system cleaner.
This is the only physical cleaning that was required in 140K miles.

Was easy to clean....just a squirt of cleaner up into the cup at the base of the injector flushed it all out.

Thanks for posting this. Been dealing with this issue for just about a year. Replaced plugs & wires, ignition coil, cleaned EGR ports, etc. First our Windstar was misfiring on 5, after having the injectors, etc cleaned, it began to misfire on 2. It idles roughly and than it appears fine, than gets worse again.

Was told by 2 others to replace the head gaskets up, heard the 3.8 was 'famous' for needing the gaskets replaced. Our Windstar is also a 1996, 3.8 with 108,000.

The '96 is not as bad as the '95 for the head gaskets. From what I read, the space between the coolant passages and the cylinder is a bit small at couple spots....and the gasket can fail at this point.
One thing to try is to pull the spark plug at the cylinder that is missing, and do a visual comparison of the electrode end as compared to a couple of other cylinders.
There are a number of places on the web that you can look to see how a plug will look for a variety of problems.....such as coolant or oil fouling.

Coolant in oil or cylinder would require prompt attention as this will cause even more serious damage......and are known symptoms of head gasket failure.

Bottom line.... There are a LOT of things that can cause a miss..... And a lot of them are cheap and easy fixes... So I would not jump right to the head gasket.....I have seen a few posts where people have advised head gaskets when it was a simple and cheap solution that solved the problem....

So lets keep up the hope that it is NOT the head gaskets.....

Great information Wiswind.

One question though:

Do you think paying for a high pressure injector cleaning from a shop would have solved the problem?

I know there are fuel tank Injector cleaner additives and I doubt they actually do that much but I was told that at a shop (dealer) they actually disconnect the fuel line and run a cleaner at high pressure throught he injectors. Of course I am skeptical.

We paid a local shop to clean the injectors, etc. The cost was $50.00, and it was QUITE dirty. Here is the link to the product they used. It made GREAT difference to our 96 windstar, but unfortunately only for about 6 weeks!!!

http://www.tri-maxx2000.com/trim2stepfue.html

That's why we are still stumped on WHAT exactly to try next on our Windstar, we were thinking head gaskets on up........as we've replaced and cleaned SO many other parts.

The crud that was causing my problem was inside the little platic cup that is over the metal end of the fuel injector.
Was very obvious when I removed the injectors and look in from the bottom.....and a quick squirt of cleaner washed it right out.

This would be different issue from a varnish buildup.

I do not know about the power cleaning for fuel injectors....Except that there are several variations of it.

Being centered around 1 cylinder.....makes things hopefully easier....as in a comparison to other cylinders can be done.

Could even be an intermittent electrical connection to the injector.....I would even try replacing the injector.....or swapping it with another cylinder (in my case.....doing the work to take it out.....I would replace it to avoid having to take things apart again if the problem moves to another cylinder). I did read a thread on flatrate about someone losing the connection between 1 injector and the PCM..... I your case....being intermittent....this could be hard to verify.

For the head gasket questions......something that I plan to try is sending in a sample of my motor oil to one of the testing places for an analysis. I have read that this is a good diagnostic tool for troubleshooting problems with the engine....before they get too big.

As far as the miss.....and a head gasket.....putting it simple (which is how I like to think) something is going someplace it shouldn't.
I would recommend having the compression checked....to see if you have a leak from the cylinder. And an oil analysis to see if anything is getting in there.

Didn't swap injectors, but did check the spray pattern....and they all spray the same! Don't know if that's a good way to accurately tell if the injector is good or bad. Didn't have a compression tester at home last night when we did the check. We are planning on buying the head gasket set today ($160.00, with torque bolts) hoping and keeping fingers crossed that it cures our Windstar's problem, if not I'll just have to throw my hands in the air AGAIN!! LOL

Last winter the windstar did overheat and had to replace the water pump, don't know if that could have caused a problem with the gaskets or not. I keep coolant in the radiator but not the overflow container.

I'll let you know what happens after the gasket swap, which will be done by tomorrow night.

Well didn't get the head gasket set in yet, had to special order them for our 3.8 as there was a mid year change (lucky me) so the parts just came in yesterday, plan on getting started this Friday as I work till 8pm the next couple of nights. I'll let you know if it made a difference with our misfiring.

If it was me doing the repair....I would seriously consider replacing the Lower Intake Manifold gaskets as well.....
I have not done this job.....but I do know that you have to take the lower intake manifold off to get to the head gasket....
The Lower intake manifold gaskets are also known for failing...and since you have it all apart anyhow.....

Well I bought the head gasket set to the the head gaskets on up, I'm not sure if the lower intake gasket was included in the kit, (would have to check) I'm hoping that this will STOP our misfiring dilemma. It gets to be a pain trying to figure out what's causing this.

Well I bought the head gasket set to the the head gaskets on up, I'm not sure if the lower intake gasket was included in the kit, (would have to check) I'm hoping that this will STOP our misfiring dilemma. It gets to be a pain trying to figure out what's causing this.

The head gasket kit has the lower intake gaskets.

What's in a Head Gasket kit? The Fel-pro set I bought (HS-9250 PT-3), newly arrived lists the following:

Head gasket Left hand
Head gasket Right hand
Water Outlet
Valve cover (x2)
Throttle body
EGR
Intake and Exhaust valve stem sealsd (x12)
Fuel injector O-ring (x6)
Valve cover grommets (x10)
Intake Manifold front seal
Intake Manifold rear seal
Intake Manifold Upper (x6)
Air Bypass Valve
Exhaust Manifold (x2)
Intake Manifold Left hand
Intake Manifold Right hand

It turned out that I needed the HS-9250 PT-1 kit with the 3mm intake manifold gaskets for my '97 3.8l... still trying to fix it, though :banghead:

Dngrsone

Well I'll know this weekend if replacing the gaskets will make the difference on the misfire. WOrking 6 days a week and long schedule has delayed getting this 'project' done faster, not to mention getting the coating off the heads to replace the gaskets!!

Even though it showed misfire on 2 (and the lousy idle and acceleration the van had) it was #3 that had the blown head gasket, so in the process found out where the coolant was going!! Ugh.

Rowdysrides
If you live around any metro area, you will find shops that specialize in combustion head inspection and repair. I would recommend that you have the heads checked for straightness and cracking. Heads are repairable even if cracked.

With the mileage on your motor, it would make sense to have the valves resurfaced and valve seals replaced...at the same shop. If the heads aren't cracked and need rewelding, this should cost less than $250. Since you are doing all that work, might as well go 1st class.

Checked the valves, they were fine and no cracks in the heads. Replaced head gaskets up, had cleaned EGR ports, cleaned injectors, bought new ignition coil in January, replaced spark plugs (Motorcraft), Replaced fuel filter, etc.........started the van tonight and STILL have a 302 code!!! I'm SOOO frustrated.

Years ago, my mother's old car developed that sound that can only be burned valves. Since the engine had a number of miles on it, I thought it was a good time to give it a thorough overhaul. I gave it the works ... new almost everthing. But I was so impressed with the condition of the "old" parts that were being discarded ... those frequent oil changes sure made everything look good!

I reassembled the engine and upon start-up, heard that same old "burned valve" sound. ....Only it turned out to be a cracked spark plug body that I reinstalled....after all, I "knew" the spark plugs were good.

I had rebuilt an engine because of failing to find a cracked spark plug!!! ... and doing a lot of assuming.

Have you tried listening to the injectors by using a length of hose? Also listen to the spark cables for a high tension snap! Inspect the cables in the dark to see if high tension leaks are visible.

Have you tried listening to the injectors by using a length of hose? Also listen to the spark cables for a high tension snap! Inspect the cables in the dark to see if high tension leaks are visible.


I will give this a try tonight right after work, thanks.

Well our misfire has been SOLVED!! Cleaned out the fuel injectors and the metal cups on the fuel rail and it's running good!! Thanks to everyone for their advice.

very good....much better than many other options.
ALWAYS try the cheap stuff first.....
One thing that I seem to have read about the windstar 3.8L engine....they DO seem to be clean inside with regular oil changes.