Isuzu Repair: rodeo isuzu 2001, upper intake manifold, petal to the metal

Question
I just sold the truck, but the person that bought it is having the same problems. I feel guilty selling him the truck, knowing that the rodeo is junk. I bought it 2 years ago for 12, 000.00 dollars from a dealer, i was at a light and the truck heated up one day. The mechanics fixed it for 2,000.00. one year later it happened again. It started also to jump, as if the transmission was going to mess up, and I realized I was going to look at a 3-4 thousand dollar problem, so I sold it for 3,300.00, and a week later it messed up and the guy is calling me and telling me to return his money. I want to help him fix it, because I do feel guilty, so what can I do? The truck keeps messing up from the same thing. I had to force the truck to drive, and when it did it ran fast, and smooth, but I couldn't push the petal to the metal in the beginning because the truck was too weak, and felt as if i were messing up the transmission. Is this truck always going to heat up and mess up, if we push the first gage up to 3, because the mechanics told me not to let the stick go higher than 3. I just want to help him fix it, or solve the same problem I had, please help.

Answer
Well Rose. The overheating is most likely due to leaking valve cover gaskets or some bypass hoses that run underneath the upper intake manifold(very common on these models). Also the transmission is probably one of the shift solenoids starting to go out. I had the same problem and the problem cleared up on its own when I had it flushed cleaned and had some non-slip tranny doctor added to the fluid. Although does it "visibly" leak any coolant? I am very sorry but the man did buy the truck as is and if it has been more than 72 hours he has no legal action he can take. The car is HIS/HERS responsibily now although we can get it back on the road for him/her okay?