91 Dakota Problems.

Hello All,

I have a 91 Dakota 318 V8 4X4 that ran good on a Sat. and then on Sunday ran like crap. The idle fluctuates and the when you drive it down the road. The truck surges like it can decide what gear to be in. It is an Automatic and has 167,000 miles on it. I would like to keep the truck but have been messing with it for awhile and can't figure it out and getting frustrated. Did tune up, wires, plugs, cap and rotor. Also changed TPS. I don't think it is fuel pump or filter but could someone point me in the right direction what to do next. Thanks and I would appreciate any advice that can be given.

Could be a vacuum leak.

Could be water in the fuel, which cloggs the sock on the suction side of the fuel pump. Try HEET or drygas, see if it helps.

I would also just change the fuel filter, unless you've done it recently.

It's always possible that you have poor cylinder compression, cracked or leaking head gasket could cause low compression, but usually presents itself as overheating and milky oil on the dipstick after driving.