Back again - same '98 4banger stock 4runner, auto tranny.

firing issue - running like an old john deere tractor (instead of a 4runner). Computer code from the shop (don't have the code designation) says firing issue is electrical in nature. Checked coil outputs by pulling plug wires off while running, coil for cylinders 2 and 3 firing stongly at the coil. Coil for cylinders 1 and 4 firing weakly (yellow and inconsistent spark) at the coil. Shop concurs that it's probably the coil, purchased and replaced same. Disconnected battery to dump code.
With new coil in place - same operational problem. Have not checked coil output at plugs - just drove the vehicle this a.m. for the first time. Now What???????

consistenly idling with one and sometimes two cylinders not firing - seems to run fairly well at anything above idle and down the road.

 

Not familiar with the 4 cyl but I take it you've already done all the easy stuff? Plugs, wires, maf, iac. Since it runs good above idle it sounds like your injectors are good...? Did you try swapping the coils?

 

I gave that some consideration but the coils are listed as two completely different part numbers (could be only because the way they mount up to the head-not sure). I'll have to check the connectors from the wiring loom to see of there is any difference in them ie nbr of contact points). I'll post back when I've checked it out. I've got 118,000 miles on the truck so if anyone is having problems with their 2.7's, chime in.

 

I had similar problem with my 98 tacoma.. I had replaced everything electrical that I could do myself plugs, plugwires, and coilpacks. I took it to a shop last Friday and found out on Wednsday that I have an exhaust valve burned up.

 

The igniter might be the issue. I wouldn't worry about valves yet because it sounds like the 2 cylinders aren't getting good spark.

 

You may be right there Brian. However, since changing out the coil pack, over the past couple of days, the engine does seem to have more power available. That being said, where do I locate the igniter? Is it as simple as following the wires back up the loom to its location (this is my first real experience with a distributorless ignition system)? How does one test said component? Thanks for the input so far!!

 

I'm not real familiar with the 2.7, but the 3.4's igniter is right on top of the passenger side fender and very easy to get to. I don't know if it's the same for the 2.7 or not. I have never had to test one, but I would guess that there should be a specified amount of voltage/resistance that would be within spec (and would be listed in the FSM). Hopefully a 2.7 expert can give you more detailed advice. Going off your symptoms, the igniter is before the coil and the coil is new, so it would make logical sense that the igniter would be the next thing to check.

 

Makes sense - I'll try to locate the info in one of the online tech pubs and see what it says. I'll keep this post going until I get this resolved. I doubt seriouslyl if I'm the only one this has happened to.