January 27, 2004I posted a topic on this once before, but I still havent found the cause. My problem seems to be intermitant. Sometimes its horrible and sometimes its not there at all. I used to get decent gas milege, at least nothing to complain about with a truck my size. Lately ive been getting about 200 miles per tank(31 gallon). it makes me wanna cry. Also, at lower rpms the engine seems to be sluggish and like Ive got a 4 cylinder under the hood. Then all of a sudden something happens and i get tons of power back. When its running poorly i have a mushy pedal, pushing it in doesnt make it grunt or bark any more or less. Its just like its a set engine speed. Ive had people tell me to check the TV or kickdown cable, but that seems to be fine. I thought maybe it was the fuel pump but i had that replaced about a year ago. Now somebody told me that it could be the cap and rotor and maybe plugs and wires. They say that since it just kicks back in all of a sudden it sounds electrical. Any help would be much appreciated!
January 28, 2004IS that thing carburated?
Sorry I missed your previous post. What are your engine specifics?
It takes three elements to get a good burn. Fuel, which sounds like you are burning way too much for what your getting. So it might be one of the other two. Spark or air.
January 28, 2004have you changed your fuel filter lately?
January 28, 2004fuel filter was replaced along with the pump last fall/winter. It is an 87 350 with TBI. Filter is a recently treated K&N. Its really starting to get to me. I can live with poor milege, I have since i started driving. Its the watching semis and dump trucks beat me at stop lights that really irritates me.
January 28, 2004Mine is a 89, 350 TBI. I have got a Spark Control Module. It controls the spark advance. I have found no test for it. Must go to a shop and hooked up to a computer. Our engines have sensor's all over them. Get your local partstore to check the distributor module. Also the distributor pick-up coil, under the rotor cap. Also the main coil itself. You have to take the parts off but they will test without charge. Sounds like a bad spark problem. If you do these thing watch out for the wiring harness plugs. I went through all these things with mine a couple of weeks ago and BROKE the plug locks on a couple because the plastic had gotten hard and brittle. Try to use as little force as possiable with the plug locks. Hope this helps.
January 28, 2004i guess i forgot to mention my ignition setup. Ive got the MSD off-road 6 ignition module and their high power coil. I also have MSD wires and i cant believe that those have gotten bad but i dont know. If the coil or the ignition module go bad, could it cause a problem like this or would it just quit functioning completely?
January 28, 2004By the way. GREAT LOOKING TRUCK!!!!!!!!!!!!!!!!
January 28, 2004The modules usally just go bad, but coils can get weak before the go out.
January 28, 2004after doing some more research on all the ignition stuff and after talking to a rep from MSD with the same truck and setup as mine, im led to believe that it might more likely be my fuel pump. It makes me so mad to think that thats what it could be since i just had it replaced a year ago. unfortunately im 250 miles away from where i had it done and the warranty is up. Im just wondering if anyone knows how to test the fuel pump pressure or if anyone knows how hard it is to replace the pump. Thanks for any advice.
January 31, 2004Is it possiable to put a inline pump into the ststem for a test? Why I ask is that I have heard changing them out is tough.
February 1, 2004ive heard of the inline pumps too and ive considered them. replacing the pump is hard and thats why i didnt do it myself last time. the pump itself is in the top of the fuel tank, which is currently holding about 30 gallons of gas. it was running good yesterday, but then whatever it is thats causing me problems took a dump again and now its really sluggish. i wish i just knew for sure what it was, whether its expensive or not.