Losing cylinders

[buievonbozo]

Hey everyone. Been a long time. Life got pretty hectic. I'm having an issue with my '97 Runner 6 cyl auto.
A few months ago, I had lost my #1 cylinder and began to lose another. Though I was getting spark, I still changed the coil packs, spark plugs and wires. Then I went ahead and changed the injectors. Changing the injectors gave me back the cylinders. Now as of last week, the engine light came back on and I am now running rough again. Feels exactly the same as before. First I lost #1 and now another.
Does anyone have an idea of what this could be. I was thinking either the computer or possibly dropping the fuel tank, cleaning it and the system etc.. Please, Help a brother out!

 

[KidVermicious]

First, stop throwing parts at your motor. Troubleshoot first, isolate the problem. Make sure you're really missing on one or more cylinders and find out which ones, then pull the plugs and compare them to the plugs from healthy cylinders. They'll tell the story.

If it really is injectors again, I think changing your filter and dropping and cleaning the tank is a great idea. But find out for sure what the problem is first.

You might want to ask a mod to move this thread to the 3rd gen forum. Guys that know this motor better may have more specific advice, and you won't get many views in this forum.

 

[mikebontoft]

food for thought: have you even changed your fuel filter yet? there's always the possibility it has failed internally, sending crap into the injectors and subsequently clogging them. You replace the injectors and it runs normal again until they become plugged. makes sense, right?

 

[buievonbozo]

I did what I could. I brought it to a mechanic that I know who helps me out every now and again. Plugs it into the computer for me, Gives me ideas and helps me with direction. When we pulled the plug, it looked dry, so we pulled another to compare to. There was a difference, not in carbon or anything, just looked dry and didn't smell like fuel. So, since everything was basically original, I didn't think it would hurt to change the plugs and wires as well as the packs while I was doing the injectors.
So what I am doing now is trying to isolate further. Why would the #1 cylinder drop this second time? I am bringing it to him this weekend to plug it in and see what other cylinder is dropping, if there is one.

 

[buievonbozo]

Mike,
The filter was changed somewhere around 100k. I am now at 170k. That was next on my list.
Thank you.

 

[buievonbozo]

Ok... here is what I found, and it's kinda confusing.
Plugged in to handheld that my mechanic loaned me, codes came up as follows;
p0300- generic multiple cylinders misfire
P0301- cylinder 1 misfire
P0302- cylinder 2 misfire
So I figured since these two are connected by the coil pack waste spark system, the problem would be the coil pack. I changed it. The truck was still running rough. So I plugged it back in to the hand held. Now the codes came up;
P0305- cylinder 5 misfire
So i pulled that pack off and swapped it with #3 cylinder and checked the plug which seemed fine. Put everything back together and started it up. Still rough. Plugged it back in and this came up;
P0300- generic, misfire on multiple cylinders
P0301- cylinder 1 misfire
P0305- cylinder 5 misfire
P0306- cylinder 6 misfire
Now, I checked these codes against a software program at my mechanics garage and it gave me a list of possibilities.
Cam shaft timing
fuel pressure
fuel injectors
multiple ignition issues (plugs, wires, coil)
So, I took a can of starting fluid and sprayed it everywhere to see if it changed anything, just incase, before i took everything apart again and nothing changed. Got everything off down to the injectors and fuel rails. Noticed that 3 plugs were a 1/2 turn loose. All plugs seemed equal in burn color. Boots all snapped on nicely with good connectivity. Checked the seating of the injector seals, seamed good and tight. Checked for breaks or wire disconnects on injector electronics, seemed good. Put everything back together, completely stumped. Started it back up and of course, still running rough. Plugged it back in and #1 and #5 came up again as well as another code (forgot it) for system coolant level being insufficient. I checked that and the level is fine. WTF!!?
Now 2 months ago, give or take, I changed the plugs, wires, packs and injectors and it ran fine, as stated before. Then everything went to hell. I don't think the timing would be off cause, though I changed all that stuff, it would not have made a difference. I have yet to check the fuel pressure. Can someone give me an idea on how to do this?
I got this truck for free, being that it did not run before, and I replaced everything and a few thousand dollars later is was fine for a couple years. Now this. I am ready to throw in the towel.