When I first start my truck, it starts fine, idles nice, but when I first hit the gas, the engine sputters a bit, then all is ok. Then it is ok for the the entire drive afterwards, it only sputters just after startup.

I changed plugs (motorkraft), wires, and the fuel filter. I pulled the vacuum line off the fuel pressure regulator to look for gas and there is none. The coil packs are a year old.

Any ideas? Again, this only happens when I first start up and push the throttle for the first time. All other times the truck runs fine.

98 with 4.6 liter.

 

might be time to clean the throttle body. there is ports inside that tend to collect carbon. also clean the MAF sensor and IAC.

would hurt to get actual fuel pressure readings either.

 

Wouldn't hurt to throw a bottle of Techron in the gas.

 

So I tried to get the throttle body off to clean, but I was only able to get the butterfly out. The EGR valve bolts were in tight, and I was ready to break them off, so i gave up for now. The tube was also in tight, impossible to turn. There are no codes for now, so I will wait until then to possibly break them. I will need some heat to help get the bolts out.

Cleaning the butterfly section did nothing to help the stuttering. The EGR passages has some carbon buildup, but appears open as i was able to put a wire into it (well up to the part where the passage turns).

I put a fuel pressure gauge on the engine and there is pleanty pressure. The fuel pump was changed 2 years ago.

Any comments welcome.

 

The throttle body needs to be removed in order to be cleaned properly.
The one on my 1997 4.6 was completely plugged at the two little holes.
I don't think i could have cleaned them with it on the truck.

 

First thing you do is break that big EGR pipe nut loose. Do this before removing anything else. Use a big *** cheater bar if need be.