Kelton

Hello all, I've got a 94 f150 4x4 with the 351W, she's got about 205k on her. She runs pretty well except the gasket where the manifold meets the pipe is leaking a little, (ill get around to that) but my question is, under medium to heavy throttle, it surges, I can feel the pull surge, pulls hard, lets off a bit, pulls hard, lets off a bit (etc...) any ideas? I'm thinking TPS, but I don't know for sure...... Any ideas? I'd really appreciate it! Thanks!