[SIZE=medium]I need some help; I have a 1996 GC 4.0. 189K mi. The problems started on a road trip pulling a trailer on a mild grade, suddenly and momentarily the engine quit and the transmission dropped out of OD and lock up and continued to do so intermittently for the rest of the trip, it may also go for several hundred miles without doing it. And then it just starts to miss and jump in and out of gear, it never completely stops running and it always starts, since then I have been replacing parts, as a mechanic with over twenty years of pulling on wrenches it’s something that I despise. [/SIZE]
[SIZE=medium]Here is a work and parts that I have replaced, header, it was cracked, full transition service, including fluid flush and adjustment (all appeared normal and in good condition) fuel pump, sock and filter, checked fuel pressure, (drove it with a pressure gauge hooked up to it, no change during episode) checked battery and charging voltage, wiggled ignition key during episode, replaced wires, plugs, cap and rotor, ignition coil Crank PS, rebuilt distributer with CPS, checked all connections to crank an cam position sensors and wiggled them with the engine running, including the CPU, could not make it miss, swapped around the ASD relay (thought I found it, it went 180 miles without missing), removed under hood power distribution panel and inspected for signs of bad connections, removed and cleaned all ground connections, removed starter and inspected hall effect trigger points for signs of foreign object damage and finally installed a rebuilt CPU. Most of these parts were due with 180K on the vehicle. The CPU was expensive and unwarranted. [/SIZE]
[SIZE=medium]One thing that’s driving me nuts is how intermittent this problem is. If it just died I could diagnose it. The vehicle is a dry country vehicle no corrosion. [/SIZE]
[SIZE=medium]Here are some things I have noticed; the tach stays stable during an episode, it never does it when cold, it takes it about 15 to 20 miles or it may take 180 mi. plus to do it again. It always starts and has never completely quit running, (most) episodes occur under light acceleration or on light grades. Episodes may last for several seconds or minutes, then all returns to normal. [/SIZE]
[SIZE=medium]Trouble codes are for multiple misfires, all cylinders and Cam PS, I have also had codes for Cat efficiency, I believe due to the missing problem. What could I be missing?[/SIZE]
[SIZE=medium]Please reply to [email protected] Thanks for your time.[/SIZE]
[SIZE=medium]Here is a work and parts that I have replaced, header, it was cracked, full transition service, including fluid flush and adjustment (all appeared normal and in good condition) fuel pump, sock and filter, checked fuel pressure, (drove it with a pressure gauge hooked up to it, no change during episode) checked battery and charging voltage, wiggled ignition key during episode, replaced wires, plugs, cap and rotor, ignition coil Crank PS, rebuilt distributer with CPS, checked all connections to crank an cam position sensors and wiggled them with the engine running, including the CPU, could not make it miss, swapped around the ASD relay (thought I found it, it went 180 miles without missing), removed under hood power distribution panel and inspected for signs of bad connections, removed and cleaned all ground connections, removed starter and inspected hall effect trigger points for signs of foreign object damage and finally installed a rebuilt CPU. Most of these parts were due with 180K on the vehicle. The CPU was expensive and unwarranted. [/SIZE]
[SIZE=medium]One thing that’s driving me nuts is how intermittent this problem is. If it just died I could diagnose it. The vehicle is a dry country vehicle no corrosion. [/SIZE]
[SIZE=medium]Here are some things I have noticed; the tach stays stable during an episode, it never does it when cold, it takes it about 15 to 20 miles or it may take 180 mi. plus to do it again. It always starts and has never completely quit running, (most) episodes occur under light acceleration or on light grades. Episodes may last for several seconds or minutes, then all returns to normal. [/SIZE]
[SIZE=medium]Trouble codes are for multiple misfires, all cylinders and Cam PS, I have also had codes for Cat efficiency, I believe due to the missing problem. What could I be missing?[/SIZE]
[SIZE=medium]Please reply to [email protected] Thanks for your time.[/SIZE]