92 z34 misses

[Gunboat]

OK,my 92 z34 was running 6 weeks ago before I broke my ankle.now that I try to start it,it misses really bad.I haven't pulled the codes yet.(I had to have more surgery done)anyone have any ideas as to what could have caused this? Thanks in advance!

[Schurkey]

There's dozens of things that can cause misfiring. Without more diagnostic work, we're just making wild guesses.

 

Do you have tools and equipment and ability to do diagnostic work? If not, it's time to hire a professional.

[rich_e777]

For about $30 you can get a GM OBD1 code reader at autozone, better than the paperclip trick but less in depth than tunerpro. Finding out if you have a specific cylinder misfire or random cylinder misfire will help things along, looking at the spark plugs and testing fuel pressure are two more simple tests you can do. Compression test and test the spark plug wires for about 15 Ohm resistance or smaller.

[RobertISaar]

test the spark plug wires for about 15 Ohm resistance or smaller.

 

15,000 maybe. 15 ohm plug wires would be a thin, solid wire and would likely generate a LOT of RFI. the taylor spiro-pro set I made in 2006 or so were fairly low-resistance, somewhere in the 900 ohm range for the longest ones. they never caused any issues that I could detect, but I don't think they were in any way beneficial either.... unless being red and 8mm instead of black and 7mm is a benefit.

[GrandRegal]

I've had the same thing happen in my Regal two separate times after coming back from vacation and both times it turned out to be failed ignition coils. Put new ones in and everything was back to normal. Like the others said there are a lot of things that could cause a miss but if the coils haven't been done in a while I would check them.

[tsilney]

Also the icm under the coils gets fried on the earlier lq1s. It's right under the front header. Great design gm. They moved it up to in 96iirc so if that's original check that out. But get the codes first.

[Schurkey]

Carbon-rope plug wires typically measure 2K ohms per foot. I've heard that used ones may measure 4K ohms per foot. 4K per foot is too much for me, I'd scrap 'em for helical-wound wires at that point.

 

I pulled a plug wire off of a 400 Ford a few weeks ago that had no continuity at all on my Fluke meter, which measures to megohms. That cylinder was weak, but not outright dead--and it only had 50 psi cranking compression, too.

 

Yes, I prefer helical-wound plug wires having a couple-hundred ohms per foot, or less--but more for durability than for performance.

[rich_e777]

15,000 maybe. 15 ohm plug wires would be a thin, solid wire and would likely generate a LOT of RFI. the taylor spiro-pro set I made in 2006 or so were fairly low-resistance, somewhere in the 900 ohm range for the longest ones. they never caused any issues that I could detect, but I don't think they were in any way beneficial either.... unless being red and 8mm instead of black and 7mm is a benefit.

 

Whoops, forgot the setting I had on my meter. Sorry about that.