My truck has rough idle, sputter, buck, misfire, backfire, no power, probable engine flooding. I have replaced fuel filter, fuel pressure rev, spark plugs wires, one misfunctioning 02 sensor, maf sensor, have tested the egr valve. Its my only vehicle and I'm stuck on ideas. My next idea would be a bad coil sence I have inspected the distributer and for vacuum leaks. The smell of gas or exhaust is also a sign of something but unsure. The misfire takes place at cold start and rarely during the rough idle. Tommorrow I am gonna clean the throttle body and egr. Probably replace the coil aswell. Any leads would be. Greatly appreciated. Also tested the fuel pressure which was at 20 psi .

 

You might have done something with the plugs but didn't mention it.
When you replaced the plug wires did you do them one at a time or all at once ?
Could you have them in the wrong tower on the dist cap or on the wrong plugs.
Firing order should be 1 5 3 6 2 4 starting from where the rotor in the dist is pointing when the #1 piston is up at top dead center. Did you move the dist at all?
Was it this bad before you started changing parts?

 

I did change plugs and wires one at a time. The truck started showing hard start symptoms when first before I changed any parts. Over time it started showing loss in power then it just lost all power even when I did get it to idle good. Now it will not idle good and will not move due to no power. It has rained yesterday and today so I have not messed with it. But the only thing I haven't checked it the coil so rather than test it I will probably just pick the part up tommorrow and see if it was the culprit all along. Would the coil being back cause misfire or act as if their was a vaccum leak?.

 

I changed ignition coil and made sure the plug wires are in correct firing order. My next guess is the distributor cap. It's just still misfiring and losing all power. Won't idle right at all.

 

You're sure you got the firing order right, but did you start with the #1 plug wire in the correct location? Did you move the distributor at all?
Usually when we replace the plugs we also change the the cap, rotor, wires and PCV valve.
How did you determine the O2 sensor was bad?
Are you sure your engine has a MAF sensor or maybe a MAP sensor?
If it does have a MAF sensor and you purchased a rebuilt unit, unplug it and see it it runs any better.

 

I replaced the rotor button and all plugs gauged to .44 with the wires to correct towers assuming it's clockwise because only one tower is label with 1. I did not replace pcv but did replace maf with no availe. I did test the maf with a multimeter and everything was getting specified voltage and resistance. So was the iaf sensor and the egr valve was good. The o2 sensor was replaced to suit a code that was thrown at the beginning of the attempt to repair.

 

If you took one plug wire off and put one plug wire on it should be right, but if you didn't do exactly that, #1 plug wire does not have to be where #1 is on the cap. If anybody had the dist out and didn't install it on the money he could have had to put the #1 plug wire where the new position for it was.
I would suggest that you remove the coil hi tension wire from the dist cap and place it next to a good ground so when you crank the engine the spark will go to ground.
Then with the #1 spark plug removed have someone crank the engine and listen for that #1 piston come up to the top, you will feel the pressure at the hole, stop when it gets close to full pop finish turning the engine by hand (alt pulley) same direction of rotation and stick a rod or piece of stiff wire in the hole so you can feel the top of the #1 piston.
When that piston is at the top of its travel the pointer over the crank pulley should be at the 0 or TDC mark on the crankshaft pulley. At that point the rotor should be pointing to the #1 spark plug tower on the cap. If it is , good ,if it ain't oh,oh ! That's where your #1 spark plug wire should be.

 

I done all and no such luck availed. Out of the blue yesterday I unplugged the iaf and the maf at the same time and the truck will idle like it's running normal. Plug etheir one up and it dies. I went to the iaf and replaced it but it did not fix the truck. But it's definately air mix situation. I figured the iaf would be the fix since I already changed the maf. What the Hell.

 

I don't know if this is the particular problem with your vehicle since we have no way to measure any voltages or signals.
When you plug in either of those components (MAF sensor IAC motor) there could be a poor connection supplying the operating voltage to the circuit and the additional drain cuts off the signals to the computer and the engine quits. You can't keep throwing parts at it because that gets expensive and frustrating. Is there any way you can get any codes from the system. That may provide some direction to start checking.

 

It doesn't throw any codes or a cel. I have tried multiple readers. But I have used voltage meters on the parts and they where at exact working specs. Also tested the connectors that plug into them. I'm lost now. Can't think of what to do next except replace every vaccum on the thing. Only thing is I can't return vaccum hoses if it doesn't fix.