I guess you can pull the plugs/wires and check them over. You can measure the wires and see what resistance values they are reading.

I'd still recommend gitting one of those diagnostics doodads...better than throwing parts at the problem trying to fix it. <img src="/forums/images/graemlins/smile.gif" alt="" />

You might try pulling the plugs and inspecting them to see if any of them look different.

I had a similar problem that went on for several months, slowly getting worse but not bad enough to throw a code. It turned out to be a bad fuel injector.

When it finally got bad enough that the truck ran really rough and it threw a misfire code, I was able to use that info and look at the plugs and see that the cylinder indicated had been running lean (HOT). That plug was totally worn and glazed/brown compared to the others that had minimal wear and were just a little bit chalky.
Unfortunately, the collateral damage was worse than just the spark plug: it took out the head gasket too. <img src="/forums/images/graemlins/frown.gif" alt="" />

In hind sight, I probably could have diagnosed the bad injector by looking at the spark plugs long before it got really bad and caused other damage.

Good luck!

I second that. My injector went the other way and started leaking fuel. It ruined the catalytic converter and the O2 sensor. Big $.

Thanks Erik I'll try to do that this week. When I changed the plugs earlier this year I don't remember that any of them looked particularly bad. Since the last time I changed them they showed evidence of being wet(running rich). That's when I put back the ISR mod and got my mileage back. As a side note I have been hearing a little pinging/ticking so that may be related and my dad's problem also seems to be better with injector cleaner added. So I'll look into maybe getting all the injectors cleaned.

Edit I'll try to remember to take some pics of the plugs.

Checked all the plugs and 1-5 look normal and in good shape. 6 is wet and smells like gas. So now the question is go for a new injector(oem), send it in for serivce or find a aftermarket replacement(napa or O'riellys)?

Napa injectors are about $50 and look to be rebuilt factory injectors. I went with Napa for mine and did the same for a friends 4runner.

Injectors from Toyota are about 3 times that price.

Another option is to send it (or all of them) in to be cleaned and tested, but then you have more down time.
http://www.rceng.com/
http://www.witchhunter.com/

I sent mine to RCeng one time, but that was 90 or 180k ago. Probably 180.

Okay thanks that makes it easy. I've got a Napa literally across the street. I think I'll send the on I take out in when I get some more money and keep it as a spare.

There is a core charge for that $50 price though, so keeping the old injector would add considerably to the cost...

I checked with Napa here they want $135 with a $15 core I about choked. So I'm going to do some shopping around. I checked TRDparts4u.com and they where $140 for a new injector. Rock auto injector list I'm looking at the GB they have a 1yr/15k warranty. I think that may be it unless one of the others is way better.