Actually Newt had a pretty decent favorability rating in 1998
From Gallup
From Gallup
Gallup said:Gingrich Fared Somewhat Better in 1998
Despite his ultimate downfall this month, Gingrich's image had actually become somewhat more positive in several polls conducted earlier this year. In February, for example, the percentage of Americans with an unfavorable image of Gingrich dropped below 50% for the first time since August of 1995. (This was generally consistent with a more positive mood that Americans had about many aspects of government following Bill Clinton's January State of the Union address.)
Although Gingrich's image dipped in a June Gallup poll, by October – the last measure before the elections – he had a partially rehabilitated image, with 42% of the public giving him a favorable image rating, and 49% unfavorable. Thus, there was some evidence that Gingrich was on the way back up in the minds of the public