Misfire - Plugwires? Injectors? Engine experts needed! (1MZ-FE) - Toyota Nation Forum : Toyota Car and Truck Forums

betz · 11-18-2007, 10:54 PM

Okay guys,

I took my car to a tranny specialist due to the thud/slug feeling I was getting while driving down the road (usually at slower as opposed to faster speeds). It really felt like a tranny problem, but he informed me that it is a misfire. After I popped my hood, revved the engine (just a bit), and placed my hand on the manifold/plenum, it became clear that he was right. I do indeed have a slight misfire.

I started to wonder if it was due to plugs/wires (which I later found had never been changed). So, I sprayed the wires with some water while the engine was running and it was pitch-black out. They indeed lit up in a number of places. Im told that this is a tell-tale sign that your wires are bad. So, I replaced my plugs (they were Densos, I threw in the OEM NGK replacements) and I replaced my wires (the reccommended OEM replacements from CarQuest). And yet, I still have the misfire.

I decided to spray my wires with water again...and found that they still light up in a number of places (by light up, I mean there is a spark/arc). So, does this mean that these wires are bad too? Or was I simply misinformed about the "just spray 'em with water" theory?

Now, lets assume for a minute that the wires aren't the problem...what do you think it could be?

I did check resistance across the coils and the Cam position sensor. They all check out just fine. However, the left-most coil was about .1-.2 ohms higher than the other two. Don't know if that is enough to make a difference. Also, I ran some seafoam through the brake-booster line a couple of nights ago...still no improvement.

Please help me figure out what is wrong. I have been considering taking it to a shop to do the injector treatment, where the run some cleaner almost directly through the injectors. Is this a good idea?

Thanks

94CoupeV6 · 11-18-2007, 11:59 PM

Coilpack

betz · 11-19-2007, 12:04 AM

Are you saying that I should replace the coil pack that is off by a few tenths of an ohm?

***ASG14*** · 11-19-2007, 12:12 AM

CEL on?

betz · 11-19-2007, 12:14 AM

Nope, my CEL has never come on. In fact, just to be sure I had my shop check for codes, and they said there wasn't anything in there...of course, they also said that if the light never came on, there can't be any codes. But, I've been told otherwise.

***ASG14*** · 11-19-2007, 12:25 AM

Yeah, thats BS. Driving with Eye8Pussies (SuperMod here on TN) tonight, there was no CEL light, but I checked the thing, and there was a code stored in the system.

Ok, since you said the coilpack was a little off, switch them around, and see if a different cylinder is misfiring then. Also, check the Injectors. I was at my mechanics last week with a Honda Passport diagnosing a misfire, which turned out to be a fuel injector. That just another thing to look into. It;s really quite hard to diagnose something like this over a computer. But I;d have to say, check the fuel injectors next.

betz · 11-19-2007, 12:37 AM

ASG14,
At this point, switching the coil pack around to a different cylinder won't do me any good, since I have no way of differentiating which cylinder is misfiring.

What should I do to test the injectors?

97trdcamry · 11-19-2007, 10:47 AM

Check your vac hoses. Especially under the plastic engine top cover. I had misfire codes thrown in my ecu because a vac hose came off. If any are cracked, replace them. Also, I would check all the grounding points in the engine compartment. Replace your underhood ground wires and this could help as well. Cost is minimal to perform both of these tasks.