This truck has a 4.9L engine with a 3 speed automatic transmission. It has approx. 109,000 kms and it runs very well for its age. I had it on the highway today because I needed it for work, probably only the 3rd or 4th time I've driven it on the highway since I've owned it. Besides revving quite high (usually around 3000 - 3500 @ 110 km/h), I noticed it was starting to hitch while driving up long inclines or hills in general. On the way to work, it did not do this, only on the way home. If you try to accelerate past 115 km/h, it would suddenly start sputtering and then 3-4 seconds later it would be fine. It almost acts as if it is running out of fuel, which it is not. Usually it would do this in 5-6 cycles and then it would work normally again. In the 45 minute drive home, it did this probably 4 times altogether.
What I want to know is whether this truck has the spark box/ignition module that seems to be a common cause of problems on older vehicles. I've read a few posts recently that were similar in nature to my problem and the solution was to clean the electrical connections and reapply new heatsink grease. There is an electrical module mounted to the drivers side inner fender that has the word "Standard" on the face of it. It kind of looks like a heatsink, about 10" x 10" square. I haven't tried to unbolt it and look for other markings, but I can also tell you that there is a flat wiring connection on the bottom front of it that splits into two round wiring harness connectors. These are both connected to harnesses that lead into the distributor (I think, one goes there for sure).
If it turns out to be the spark box at fault, are these replaceable with aftermarket parts made by Accel or others? Or would I have to go to the dealer for a replacement? It seems to me that the first car I owned, a 1986 Tempo, had the same type of problem. It would suddenly bog out and sometimes stall. I remember replacing some type of ignition/spark box, seems to me it may have been the same part, but that was over 12 years ago.
Thanks for any info. Sharky