In a spark chamber and counter experiment at the Princeton-Pennsylvania Accelerator we have investigated the decay K+-->e++π0+ν. A Dalitz plot of 1393 Ke3+ events agrees well with vector coupling. The π0 energy spectrum was investigated to determine the energy dependence of the strong-interaction form factor f+ which is a function of q2=MK2+Mπ2- 2MKEπ for K+ decays at rest. For a linear expansion f+(q2)=f+(0)(1+λq2Mπ2), we obtain λ=0.016+/-0.016, which agrees well with previous measurements of λ for Ke3+. Assuming the interaction is dominated by a J=1-, I=12 intermediate state of mass M, such as the K* resonance at 890 MeV, we obtain M=(1180-387+∞) MeV. This result is consistent with K* dominance but also with no energy dependence for f+. The value of λ for Ke3+ obtained in this experiment agrees with the weighted mean value <λ0>=0.010+/-0.018 obtained from four Ke30 experiments and thus offers no evidence for violation of the leptonic |∆I|=12 rule.