I have an 98 with the 360, I just got it about a month ago and it has ran fine until today, Just all of a sudden when I was going down the road it started HARD missing, bucking and everything, doesnt even idle very smooth at times but it really seems to miss under any kind of a load. No check engine light, no codes showed up. I tuned up when I got it, so I don't suspect ignition, but I think maybe fuel is the problem. I have had the following situation ever since I got it: If you just turn the key all the way to start it will take 4-6 seconds before it will start, if you pause at ON until the fuel pump cycles off it will start fine. I thought there might be a check valve or something bad that was letting the fuel drain out of the rail, but know I suspect my two problems are related. Any ideas ? Many thanks....

 

Does it miss like this close to a 1/4 tank? Mine was chugging really bad everytime it got close to a 1/4 tank and I had to replace my fuel pump. They usally last 80,000-100,000 so you could pressure test your system and see if that might be what the problem is.-Dave

 

No I have about 3/4 of a tank of fuel, but I am suspecting that the pump assy may be an issue. Do you know what the proper psi is at the rail by chance ? Thanks for your reply...

 

35 to 45 PSI.

 

depends if it is a returnless system or not... 35-45 for a return type of fuel system, 49 psi for a non-return type.

measure the fuel pressure and let us know... probably the pump. how many miles on it? I've heard that the fuel filter can become clogged depending on what type of gas your using, but it's all in the fuel pump assembly anyway and you cant change just the filter...

 

Put a gauge on the rail today and there was zero pressure when I first hooked it up, turned key to on, waited for fuel pump to stop...still no pressure, cranked the truck over and it came up to around 40 psi when it started. Then I turned the key OFF and the pressure went right back to 0. This confirms that there is something bad in the Regulator assy causing the fuel to drain back out of the rail. If that is correct then I think that would be why the truck takes a long time cranking to fire up. So of course you have to replace the whole unit so I ordered one today and I will give that a shot. I still think my missing problem is fuel related, maybe there is a check valve bad in there that is causing both problems ? Thats what I am hoping anyway. I really dont think it is an electrical problem, I pulled each wire one at a time and I have spark at all 8 and of course still no engine codes have been thrown. Am I thinking right ? I don't feel like I wasted my 200 bucks, the truck has 97000 miles on it, cant hurt to change the filter/pump/regulator assy I wouldnt think, plus I am convinced that is the only thing making the fuel drain from the rail. Any more thoughts or suggestions ?