1998 Toyota four runner 3.4 liter automatic, sputtering.

The truck idles great, in neutral, or park, at any RPM, but in gear,
it sputters, almost all the time, like, it's not getting the gas. At
cold start, it's fine, at first, for a minute, or so. Then, it
sputters, almost continuously. It first showed the problem, while on a
five hour constant drive. On 30 minute, constant drives, it was fine.
When it first happened, it only happened a few times, on the long
drive, & it got worse over time. It doesn't burn any more gas, than it
should, it just sputters. The yellow engine light, under the fuel
gauge, doesn't work, & the windshield wash light is on, & the brake
light is on too. There is lots of windshield wash, & the brakes are
fine. I'm wondering, if these lights are all related. The brake light
only came on after having been serviced, to put the truck on the road,
as I just bought it a couple of months ago. I get no code, as the
service engine soon light is not coming on when I turn the ignition
switch to the on position. The brake light will sometimes flash
momentarily while the truck is sputtering. The previous owner stated,
he blew an ignition coil pack ( there are three...one per cylinder),
while giving a boost to someone. The truck was running perfect for
weeks after I bought it. I have filled up, & put EFI cleaner in the
gas tank, but it's still the same. What, should I look for? I'm
assuming, there is no vacuum leak, as the truck runs fine in neutral,
at any RPM. I will get the codes checked, as soon as I have time. Are
these trucks, known for any common tips, for this type of problem?
Thanks, for any input, you may give.