I got an 88 K5 Blazer and before i start throwning parts at it i wanted to ask a few questions. The engine is miss firing badly. I changed the cap and rotor. The distributor was removed because one of the bolts that holds the cap down broke but i put the distributor back in the same position it came out. Is there a way to test the plug wires with a multimeter? There is fuel going into the throttle body but could the fuel pump be starting to go? Ive also thought that a fuel pump is either working or not? Im also thinking that the *** gas now a days could be affecting the running of the engine. Any imput would be great. Thanks for reading.  

If plug wires have not been change for a long time, change them. Generally they should be about 10,000 ohms per foot but this is not always best test because they can break down under heat and current.  

While a spark plug wire may look good on the outside, internally it can be brittle and have a ton of resistance. If your cap and rotor needed to be changed, your wires probably need to be changed too.

If a fresh set of wires doesn't solve your problem, I'd start with a timing light and see where your timing is at. checking timing is easy on these trucks (I've got a '92 C1500) you just have to unplug the timing control on the fire wall. It's behind the black cover on the passenger side of the firewall, a single brown wire with a weather pak plug. Any service manual tells you about it.

The other culprits if your timing's not off is either the ignition module or the electronic spark control module.  

check the coil. stock plug wires should have about 1,000 ohms of resisance per foot not 10,000 ohms.  

OK thanks for the input im going to check that first. People have been telling me that it might be the fuel pump but there is fuel going into the throttle body. Also how the the coil checked?  

1978k-20:
check the coil. stock plug wires should have about 1,000 ohms of resisance per foot not 10,000 ohms.

Guess again, HEI ignition has a much higher resistance in wiring. The higher resistance helps suppress ignition noise. 30 or 40,000 ohm in 3 or 4 foot of cable is not a problem for HEI. What happens is cable might ohm check okay but break down under current. ALso insulation is prone to break down with age and cause leakage and reduce spark energy. New wires is a good starting point.  

and the fuel pump does not work or not work, is it a very rough jerk or a bog down, a bog down the fuel pump might not be putting out enough pressure. and they suck to change in blazers, if mine goes bad i am tempted to cut a whole in the floor, uggggggggg, it sucked on the one i replaced at work.  

It is not that bad to change "IF" you empty the fuel tank first before you drop it. Beside while it is down it is a good time to check the condition of the fuel line to it as well.  

30 to 40,000 ohms is way to high for resistance. 1,000 ohms per foot the standard is was taught to use when the spec is not give on mitchel or all data.  

1000 ohm per foot is about right for non suppressor wires on old ignition system but not today. Average current of spark is less than 10 ma and even 30,000 ohms is only going to drop voltage 300 voltage which is peanuts with 50Kv. Resistance wire helps soften spark a bit and also increase duration of it a few micro seconds because it times a bit longer to build up voltage at gap and a bit longer to discharge it.  

a video would be nice of it, easier to figure stuff out when you can hear or see it,haha  

a video would be nice of it, easier to figure stuff out when you can hear or see it,haha, can tell a diff by the way it misses if you can hear it  

Ok ive got an update but still no progress. I replaced the spark plug wires and changed the fuel filter. But still is idling very erraticly and doesn't rev out like it should. It also is backfiring out the throttle body. I have Rotated the distributor to get the timing close to zero but with it idling so erraticly it is tough to get it exact. I next rolled the engine to TDC and pulled the cap off it and the rotor is pointing at the #1 cylinder just checking to see if it is off 180 degrees. Could the distributor be bad? So now im thinking it has a vacuum leak. When pulling the vacuum line off the tranny the idle smooths right out and when i plug it back in it wants to kill it? I'm kind of confused at what is going on now any more feedback would be great. Thanks for reading  

Starting trouble has been fixed. After going through the whole ignition system it ended up being the fuel injectors. I had a backup throttle body and robbed the injectors off it and the Blazer fired right up and it has never run better. Thanks for all the information.