finally fixed the 1996 explorer running bad

[dusty20]

Ok so earlier I posted how rough my 1996 4.0 was running. It had rough idle and missed on a couple cylinders. It would run pretty decent after around 3200 rpms but terrible below that. I started with plugs and wires but that didn't fix it. I replaced the injector on the cylinder that was misfiring but that didn't quite fix it and then I had a bad fuel leak!

The solution was to replace all 6 of the injectors and replace the gaskets between the upper and lower intake manifolds. The problem was that it had a vacuum leak because the rubber seals had gotten hard and cracked and the injectors started leaking between the plastic part and the metal part generally caused by old age. Replaced them and now it runs great! I am excited about it. Unfortunately it isn't the cheapest fix but it works now and hopefully can recoup some of the cost in better fuel mileage.

 

[robertoa1a]

Rarely has anyone with a 4.0l ever needed the injectors replaced. The gaskets are more of a problem.

1. Welcome.

2. The advice you give here is permanent, so use some wisdom.

3. It ails me to hear that you didn't read the other topics within this community, all

relating to the dreaded intake problem.

 

[my98nnj]

As Robertoa1a said, it was most likey your intake gaskets causing the issue, not your injectors.

Glad it's running OK, but at a much inflated cost to you.

 

[dusty20]

yes, that probably caused the problem but the fact that it was pouring gasoline on the floor was caused by the injectors not being sealed, as one was replaced another one would start to leak until all had to be replaced.

 

[Turdle]

Oh, I wouldn't be so quick to rule out dead injectors.
A vacuum leak will rarely cause a dead miss.

 

[dusty20]

Well i asked several questions here and even shot back and forth with people about what it could be the symptoms were bank 1 being lean, misfire on cylinder 4, rough idle, felt like it would flip a switch at 3200 rpm and have decent power. if it was a vacuum leak i could understand that would make the bank 1 lean, cylinder 4 is on bank 2 though...

I replaced plugs and wires because it is a very high mileage truck and thought it could possibly fix the misfire on 4 but it didn't work. I didn't think it could be the timing because only cyl 4 misfired instead of 4,5 and 6. i didn't think it could be the crank sensor because then all of the cylinders would misfire, and i thought it would have to be a really strange occurance that the coil would only choose cyl 4 to misfire since they are all on the same coil pack but that has happened before. I also tested it and knew that i was getting spark to cyl 4, but just getting spark doesn't mean it was in time or strong enough to not cause the misfire. When I replaced the cyl 4 injector that is what made the most sense to me and I believe the initial removal and reinstalling the fuel rail is what cause the others to start leaking, checked the o-rings and replaced them all everytime I removed it just to be safe (they are like 2 dollars for a 4 pack).

I guess i didn't really mean for this to be a informative post more so a "I'm really happy that it is fixed and runs great now" post. For a truck with a hair under 204,000 miles it still runs good!