weedahoe

I bought my wife a 95 GT 5.0 stick a few months back with 90K miles. The car was from an older man who traded it for a newer Mustang. He has done several mods to it including an aftermarket cam, pulleys, air intake and an MSD distributor/wires but OEM coil.

The car runs hard, fast and good. But recently it has developed a skip. Sometimes it feels like it is running of 6-7cyl and not all 8. Believe me, you can tell the difference when it is running right. It pulls hard when everything is working. Also when you drive it, it will sometimes backfire a bit. Now I did replace the plugs and still no difference. It is usually worse when everything is cold and doesnt do it at all or not as much when it is warmed up. I bought a can of carb spray and sprayed the airintake to head seals as well as all the vac lines. I sprayed the EGR and brake booster lines but it never idles any differently. So I think I am safe on the vacuum leaks but please correct me if I am wrong. Because of the aftermarket cam I do not know where the timing should be at BUT the distributor is tight as I tried to turn it and it would not move. This is not to say that the timing chain hasnt stretched. What am I missing? I can buy an OEM coil for about $17 from AZ or an MSD coil for about $45-50. I can get the cap and rotor kit (replacement for mine) for about $28. While I know these are items that can be affected, am I missing anything else that ic an look at before I start throwing money at what may or may not resolve the issue? Thx

weedahoe

can someone please give some sort of inclination on what the issue may be or if I have covered it all?

82_4Door

I would be looking at dist, wires, and timing. Missing and backfiring sound spark related to me. Did he really replace the dist, or just a MSD cap? If it's not a stock dist, how does it splice in to the Ford harness? does the wiring look to be well done? Also need to make sure dist had the right gear for roller cam. Steel cam will chew up the dist gear if it's not steel as well. This would be a bad thing.Would likely show up as slop in the rotor. May just be a plug wire grounding against something. Pop the hood at night, and look for arching. Pull the spout and check the timing just to eliminate that as a possibility.

7upedition

I'd verify timing first, base timing should be around 10-12* if your running pump 87 gas. Have you checked the contacts on the rotor and cap, may be worth replacing to eliminate as a suspect, it's probably never been done before, it that doesn't cure it, I'd pull the distributor and inspect the teeth. Do any of the wires have burn through holes from the headers?

weedahoe

It is a just a MSD cap I am sure and not the entire distri, I have chked the wired for breaks and grounds but havent found any although I havent checked at night (like I know I should). I have a timing gun so I can check for the 10-12* of timing but is that on a stock build or with an aftermarket cam? Or does it matter? I have not pulled the distri to check the gear but will this weekend. Oddly enough, the car has run great for the last 3 days. It runs fine with no missing and pulls hard as it normally does. I just thought I would throw that out there. I will go over everything today when I get home from work. THX guys.

82_4Door

If the distributor is stock, then youprobably don't need to worry about the gear. Just pull the cap and see if there's play in the rotor. Check the condition of the cap and rotor. Arching inside the cap will produce what look like pencil lines on the inside of the cap. Replace both if they have this, or if the end of the rotor looks chewed up from arching. Having seen both, I think the stock cap and rotor are better quality than the MSD. The MSD is really cheap from Summit, and it looks cool, which is why I bought it. Stock timing should be fine for trouble shooting. If you run regular gas, you can only go so far without pinging anyway. Look for evidence of arching where plug wires lay across metal brackets or valve covers. Also headers. The plug wire will usually have a black mark where it's been arching. If you still can't find it, try misting the engine with a hose to see if it starts missing again. Maybe it only does it when it's damp outside.