General Engine Misfire (1 Viewer)

I went to get in my '99 this morning and when it cranked up, I noticed a distinct misfire (it ran fine the last time it was driven) It will idle, and drive, but at least one cylinder is not firing. Seems worse at low rpm's, and smoother (but still obviously misifiring) at higher rpms. The check engine light came on and I got it read at Autozone; it has 2 codes--a general engine misfire and a misfire on #8 cylinder.

Without going through a parts swap, here's what I have deduced: Either a coil or injector has gone bad, possibly on #8. (I have seen on other model vehicles the check engine light point to a specific cylinder and that not be teh one broken). Can I test these with a multimeter? Do you any of you have the resistance readings that they should be? Or any other ideas that might be wrong?

SC Joe said:

In my '99 I noticed a distinct misfire. It has 2 codes--a general engine misfire and a misfire on #8 cylinder. Can I test these (coil packs and injectors) with a multimeter? Do you any of you have the resistance readings that they should be?

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Use your meter to check the resistance of all eight coil packs and injectors. My guess is the reading on coil pack #8 cylinder will be way different that the other seven coil packs. If they all read the same, try checking them when hot. If they still check the same, I'd suspect a spark plug.

I checked both my service manuals, and they both said that I need to spark test them--basically pull a plug, ground it, turn the engine over, and see if it has a spark. I didn't think that doing this was a good thing (I remember issues with GM HEI ignitions and doing this) but anyway, that's how I had to test them.

I did a resistance check on all 8 coils, cold, and man, did I get some whacked out results. The coil that ended up being bad looked just as normal (resistance wise) as all the others. I checked resistance from the four connecting pins in each coil in every combination to each other, and to the primary lead. Several had OL (open circuit) on the same pins; others did not. There was no real way other than a spark test to differentiate a good coil from a bad one.

Anyway, I see why Toyota says to test it like that. And it ended up being the #7 coil that was bad. It cost $108 from the dealer (no local parts stores had one, and I needed it asap).

I just hope this doesn't get to be a habit.

SC Joe said:

I checked both my service manuals, and they both said that I need to spark test them--basically pull a plug, ground it, turn the engine over, and see if it has a spark. I didn't think that doing this was a good thing (I remember issues with GM HEI ignitions and doing this) but anyway, that's how I had to test them.

I did a resistance check on all 8 coils, cold, and man, did I get some whacked out results. The coil that ended up being bad looked just as normal (resistance wise) as all the others. I checked resistance from the four connecting pins in each coil in every combination to each other, and to the primary lead. Several had OL (open circuit) on the same pins; others did not. There was no real way other than a spark test to differentiate a good coil from a bad one.

Anyway, I see why Toyota says to test it like that. And it ended up being the #7 coil that was bad. It cost $108 from the dealer (no local parts stores had one, and I needed it asap).

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There must be some diodes or transistors inside the coil pack housing that make resistance testing inconclusive. That must be why the FSM doesn't give any resistance values. Now we know for sure resistance testing doesn't work on coil packs. A guy at work lost one on his Tundra with the 2UZ-FE engine and he ordered a replacement through Autozone for $63.

jp213a said:

There must be some diodes or transistors inside the coil pack housing that make resistance testing inconclusive. That must be why the FSM doesn't give any resistance values. Now we know for sure resistance testing doesn't work on coil packs. A guy at work lost one on his Tundra with the 2UZ-FE engine and he ordered a replacement through Autozone for $63.

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Might be different for the LC; Autozone here wanted 3 days and $92, Advance had it for $88 and Monday delivery. Local Toyota dealer had it now and wanted $108.

SC Joe said:

Might be different for the LC; Autozone here wanted 3 days and $92, Advance had it for $88 and Monday delivery. Local Toyota dealer had it now and wanted $108.

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Autozone online shows $62.99 for a 1999 LC coil made by Wells, part #C1173. The 2000 Tundra with the V-8 takes the same part number. The guy at work who ordered one for his Tundra got it the next day for around $65 (probably $62.99).
http://www.autozone.com/servlet/UiB...Store|~REGULAR+PARTS+LOOK+UP|~Coil+-+Ignition

jp213a said:

Autozone online shows $62.99 for a 1999 LC coil made by Wells, part #C1173. The 2000 Tundra with the V-8 takes the same part number. The guy at work who ordered one for his Tundra got it the next day for around $65 (probably $62.99).
http://www.autozone.com/servlet/UiB...Store|~REGULAR+PARTS+LOOK+UP|~Coil+-+Ignition

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I dunno; I'm just telling you what they told me when I went to Autozone.

I had the same problem a few months ago, it was cylinder 3 that was acting up - I had a OBD II scanner that told me - so I just swapped the coils from number 1 and number 3. Started it back up and the misfire moved to #1, so I just replaced it and it was good to go after that.