car is missing/spitting, what's wrong?

[1990AWD]

here's the story; The other Friday I was cruising around, running the car real hard and revving high. my car loved it and ran like a dream until Sunday when I started and ever since it was been sputtering/spitting/missing. it happens all through the rpm range and just runs real rough and slower than normal. I replaced the spark plugs, fuel filter and even tried a boost leak test. My boost leak test wasn't really helping because I couldn't hear any hissing. All the air I put in the intake was coming out the engine crankcase vent. That says headgasket to me, but the head is freshly shaved, has a MLS headgasket and arp head studs. Other than that the car is essentially stock. I really want my car back to normal and need all the advice I can get...and I sure hope its not the headgasket because then I'll have to get rid of the car (I can't afford this kinda problems right now). Thanks for now.

 

[Jiggalude]

Why would air coming out of the crankcase vent be a headgasket? Do you have any coolant in your radiator around the filler neck? Is the car smoking at all? My guess would be you blew a hose off while you were driving around. I would check all your couplers and redo your boost leak test, but this time cap off the little nipple on the side of the valve cover. Also, it never hurts to take the negative terminal off your battery and do an ECU "reset."

 

[Indian]

Did you check the rest of your ignition components? I had a bad coil pack,everything was fine,and then the one day it had smiliar symptoms to what your having. It only got worse as time went on obviously. Also are you having any idling problems?

 

[1990AWD]

Why would air coming out of the crankcase vent be a headgasket? Do you have any coolant in your radiator around the filler neck? Is the car smoking at all? My guess would be you blew a hose off while you were driving around. I would check all your couplers and redo your boost leak test, but this time cap off the little nipple on the side of the valve cover. Also, it never hurts to take the negative terminal off your battery and do an ECU "reset."

well isn't the only way air can get from the intake to the crankcase through a bad headgasket or bad rings?
I will try again and do that ECU test.

Did you check the rest of your ignition components? I had a bad coil pack,everything was fine,and then the one day it had smiliar symptoms to what your having. It only got worse as time went on obviously. Also are you having any idling problems?

I haven't checked the coil. wires are basically new. How would you check the coil to see if it is weak?
The car will go down to 500 rpm but then back to 750 rpm. It runs rough with a bad miss in it but it will run consistently at 750 with no surging.

Thanks for the info guys! I will try a couple of those things later today.

 

[Indian]

You can test the coil with a DMM. You can first measure the resistance on the connector by holding your positive lead on the bottom single pin,and switching the negative lead between the top two pins. You should see around .70 - .86 ohms. To test the actual coil pack you can but your postive lead in terminal 1,negative lead in 4,and then 2 and 3. These values should be between 11.3 - 15.3 k ohms.

 

[1990AWD]

You can test the coil with a DMM. You can first measure the resistance on the connector by holding your positive lead on the bottom single pin,and switching the negative lead between the top two pins. You should see around .70 - .86 ohms. To test the actual coil pack you can but your postive lead in terminal 1,negative lead in 4,and then 2 and 3. These values should be between 11.3 - 15.3 k ohms.

okay thanks, I'll do that tomorrow.

and as far as resetting the ECU (taking the positive off the battery for some time and putting it back on) didn't help. it actually made it idle a little worse (in terms of idle speed)

 

[1990AWD]

You can test the coil with a DMM. You can first measure the resistance on the connector by holding your positive lead on the bottom single pin,and switching the negative lead between the top two pins. You should see around .70 - .86 ohms. To test the actual coil pack you can but your postive lead in terminal 1,negative lead in 4,and then 2 and 3. These values should be between 11.3 - 15.3 k ohms.

I measured the pins on the coil pack but I'm getting 1.4 ohm. Everything else tests fine. The power transistor seems to be no good also. When I test it like it says in my Haynes manual, all three of my transistors test bad.