Mofo Party Plan, was released in September 1987 and peaked at No. 148 on the Billboard 200 chart, a significant improvement over their earlier albums. The band immediately embarked on a two and a half month North American tour to promote the release, accompanied by Faith No More as support who were also promoting their new album Introduce Yourself. During this period, however, Kiedis and Slovak had both developed serious drug addictions, often disappearing for days on end. Slovak died from a heroin overdose on June 25, 1988, soon after the conclusion of the Uplift tour. Kiedis fled the city and did not attend Slovak's funeral. Irons, troubled by the death, left the band; following years of depression, he became a member of the Seattle grunge band Pearl Jam in 1994. 1988–1989: Frusciante and Smith join DeWayne "Blackbyrd" McKnight, a former member of Parliament-Funkadelic, joined as guitarist, and D. H. Peligro of Dead Kennedys joined as drummer. Kiedis re-entered rehab for 30 days, and visited Slovak's grave as part of his rehabilitation, finally confronting his grief. Three dates into the tour, McKnight was fired for lack of chemistry with the band. McKnight was so unhappy he threatened to burn down Kiedis's house. Peligro introduced Kiedis and Flea to teenage guitarist and Chili Peppers fan John Frusciante, who brought a darker, more melodic rock style to the band. Frusciante performed his first show with the Chili Peppers in September 1988. The new lineup began writing for the next album and went on a short tour, the Turd Town Tour. In November, Kiedis and Flea fired Peligro due to his drug and alcohol problems. Following open auditions, they hired drummer Chad Smith in December 1988, who has remained since. According to Smith, "We started playing, and right away we just hit it off musically." The Chili Peppers began work on their fourth album in 1989. Unlike the stop-start sessions for The Uplift Mofo Party Plan, preproduction went smoothly. However, the sessions were made tense by Beinhorn's desire to create a hit, frustrating Frusciante and Kiedis. Released on August 16, 1989, Mother's Milk peaked at number 52 on the U.S. Billboard 200. The record failed to chart in the United Kingdom and Europe, but climbed to number 33 in Australia. "Knock Me Down" reached number six on the U.S. Modern Rock Tracks, whereas "Higher Ground" charted at number eleven and reached number 54