I have a 93 F150 w/ 5.0L that a Jasper reman motor was installed. I looked at engine before intake was put on & it had a roller cam in it. The mechanic told me that all 5.0L engines from 87 up had them. Could this be causing my miss? (Thread called Help with miss)

 

I didn't look at your other thread but are you using the firing order for a roller cam engine? The roller cam 5.0 engines use 13726548 and the base 302 engines use 15426378.

 

I am using the base 302 firing order, but I figured that if the firing order was incorrect it would ever idle or run right.

 

what are the specs on the cam. truck 302's didnt get roller cams till late 92 early 93. so i have a feeling the cam in there is meant for a car with the wrong lob seperation. is your 93 equipped with mass air?

 

It is not Mass air equipped. OK, here is the history on the truck. Ran fine til 186,000 miles then #8 cyl went away, 0 compression. Replaced with Jasper reman, ran fine at first, then check engine light came on then driveablity problems started. It misses under a load. The mechanic that I had working on it checked everything & then started throwing parts at it. Replaced distributor, coil ignition module, EGR valve & position sensor, o2 sensor, fuel pressure reg., injectors, transmission & convertor. Then at about 200,000 that engine developed a knock whick turned out to be piston in #7 cyl. Replaced engine problem still continued. Had another mechanic look at it, he said replace the computer. After that the truck ran fine. At 244,000 while on vacation fuel pump went out, replaced it, ran fine until I got back from vacation, then it started to miss under load again. Replaced cap, rotor, plugs, wires, FPR, & computer. Still missing under load. Was told by Jasper that the truck had a roller cam in it from the beginning(not sure, didn't see it) but 1st and 2nd motors were rollers. Please help!! (sorry for long post)

 

My 1992 Ford F150/250/350 Serivce Manual says that the 1992 302/5.0 had roller cams. And every rebuilt engine web site that I have looked at says that the 92 and up 5.0 for the truck is a roller cam engine.

 

I have an F150 4wd with a late 1991 mfg date that has a 5L with a roller cam. I can't swear that this is the original engine. It is not the Mass Air Flow set up.

Steve

 

pull codes and tell us what your getting. make sure your plug routing is correct and no wires touching each other. what brand/style plug are you using?

 

I am currently using Autolite # 25 but was using motorcraft. Codes are 311 & 332. Wires are FMS that are routed and seperated at several spots.

 

Here is an update on driveabilty problem. I did some exploring with a vacuum pump & found a couple of broken/plugged vacuum line. Traced everything out and fixed all the lines. I no longer getting the check engine light but miss under load is still there. Help.