Could be timing,check your might be your coil. Could be you tfi sensor on the dist. ..make sure your dist and dist. cap are tight and not moving under load.....very rare but ive seen it happen.
!!!!!!!!!!!!!!!!!!!!!!new 5.0 but have one problem!!!!!!!!!!!!!!!!!!!!!!!!!!!!
- Thread starter mymstngGT
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dont scare me like that it doesnt sound like a head
Make sure none of the plug wires are throwing an arc to something close to them and make sure you don't have a cracked plug. Same thing happened to me with my GTO. I had headers installed and the shop cracked a plug reinstalling them after the header installation. I pulled the plug and couldn't see any cracks until I used alittle bit of grease and ran it over the insulators and there it was. Changed them out and it ran great. It would idle great but under load, would hasitate,backfire and fall on its face.
If it was a fouled out spark plug or something, the car would rattle like hell during a certain RPM range. I was going to say fuel pump. Have someone turn you car on and you leaned down by the fuel tank to hear the pump come on.
But a fuel pump going bad will make like a loud popping noise, like some bad gas in your tank or something. And it will eventually cut off on you, you wait about 2 minutes, it fires back up, you ride about 2 miles, and it will cut off again.....Just my .02
But a fuel pump going bad will make like a loud popping noise, like some bad gas in your tank or something. And it will eventually cut off on you, you wait about 2 minutes, it fires back up, you ride about 2 miles, and it will cut off again.....Just my .02
I had a very similar issue when I installed my heads, cam, intake. My car idled like crap and felt like it was running on 4 cyl, which it was. It vibrated really bad and I had explosions in the exhaust. The explosions were due to the excess fuel exlpoding in my headers. My plug wires were wrong due to the Haynes manual only giving the non-5.0 firing order. Check your compression first. If that is good I would bet money you're firing order is wrong. I'm also assuming it ran fine before you tuned it up. Also make sure you're timing is at least 12 deg BTDC.
sunds like way tooooo much timing
check your fuel injectors it can be that you might have one thats failed. plus does your car smoke right now and if so what color?
I had an 88 Gt that did this and I did a thorough tune up and adjusted the fuel pressure up a bit. Do this, put brand new plugs in it, taking all tools needed to pull plugs, and do a first through third run. Pull over immediately and pull the new plugs. (Old school tuning method) Look at the plugs and see what color they are. If they are black you have way to much fuel, white, there isn't enough. Depending on what they look like just adjust fuel pressure or timing accordingly. Works for me every time. You will want to get that thing on a dyno for a tune even after you correct your problem. This is just to give you a decent "base" to start with and it will make sure you don't run into further problems.
cant believe no one has asked this: what kind of valve springs are on the car? you could be floating a valve.
if your talking about a bent valve and if its hard to fix - id say yes. you have to buy another valve, pull the head, use a special tool to remove the valve spring, slip valve out and re-assemble. and even doing this you can never be to sure it didnt cause damage the head or its seat.
Yeah,he is right.i my problem was a bent valve,So i had to pull the heads out,buy a new valve,Put it on and just to be safe i took th heads to a machine shop and got them polished up,resurface,and a copression check.
That fixed my problem,But lets hope thats not the problem with your car.
Yes, timing would cause some pretty nasty issues.
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