It might be of some surprise to any person familiar with the current Anglican meltdown in the United States that the Protestant Episcopal Church used to have a sizable number of clergy and laity who actually subscribed to the doctrines of the Reformation. Moreover, there was a sizable Evangelical movement within the Episcopal Church which promoted Bible study, testimonies, personal evangelism, and conversion. In the early part of the 19th century a good number of priests and bishops joined with other Protestant Christians to prohibit the drinking of alcoholic beverages, going to the theater, dancing, gambling, amongst other practices readily common among enlightened Episcopalians of today. Consider the following recommendations of the Committee of Five Bishops on Ritualism:
The Committee report the following as the matters upon which they respectfully recommend legislation:How many of these practices are nearly universal in Protestant Episcopal churches nowadays? I'd say nearly all of them are accepted without question. Consider this declaration made by the bishops of the Protestant Episcopal Church in 1871 in response to the baptismal regeneration controversy (whereby a large number of the Episcopal constituency wanted to change words in the baptismal liturgy to make the service fit more closely with the theology of the Articles):
The recommend that certain acts in the administration of the Holy Communion, and on other occasions of public worship, hereinafter enumerated, be prohibited by canon; to wit:
(1) The use of Incense
(2) Placing or retaining a Crucifix in any part of the Church
(3) Carrying a Cross in procession in the Church
(4) The use of Lights on or about the Holy Table, except when necessary
(5) The Elevation of the Elements in the Holy Communion in such manner as to expose them to the view of the people as objects toward which adoration is to be made, in or after the prayer of Consecration, or in the act of administering them, or in conveying them to or from the communicants
(6.) The mixing of water with the wine as part of the service, or in presence of the congregation.
(7.) The washing of the Priest's hands, or the ablution of the vessels, in the presence of the congregation.
(8.) Bowings, crossings, genuflections, prostrations, reverences, bowing down upon or kissing the Holy Table, and kneeling, except as allowed, provided for, or directed, by rubric or canon; it being provided that reverence at the mention of the name of the Lord Jesus is not intended to be disallowed; and it being further provided that private personal devotion, before or after official ministration, is not to be understood to include or justify any of the acts prohibited.
(9.) The celebration or receiving of the Holy Communion by any Bishop or Priest when no person receives with him.
(10.) Employing or permitting any person or persons not in Holy Orders to assist the Minister in any part of the Order for the administration of the Holy Communion. 
The Bishops, in council, with an extraordinary unanimity, have, during the present Convention, set forth a declaration touching our Offices for the Baptism of Infants, in the following words:
"We, the subscribers, Bishops of the Protestant Episcopal Church in the United States, being asked, in order to the quieting of the consciences of sundry members of the said Church, to declare, our conviction as to the meaning of the word ' regenera'e,' in the Offices for the Ministration of Baptism of Infants, do declare, that, in our opinion, the word ' regenerate is not there so used as to determine that a moral change in the subject of Baptism is wrought in the Sacrament."
This declaration was made, in the loving hope and confidence that many consciences might thus forever be freed from false impressions, which have been prevalent, concerning the teaching of the Church as respects spiritual religion and personal piety. We exhort you, brethren, to be ever mindful of the tender love of our Master, Christ, for the little children, and to think highly of the privileges to which those are admitted, whom, through the agency of His Church, He still takes into His arms and blesses. We entreat you to regard them as His own children by adoption [5/6] and grace--as heirs of GOD--to be, brought up in the nurture and admonition of the LORD. Let them not suppose that the faith, and the prayers, and the obedience, of little children, are lightly regarded by the Father of Mercies. But remember, also, that Baptism does not supersede the necessity of repentance, of justifying faith in Christ, growth in grace, and in that "holiness without which no man shall see the LORD." We exhort all the members of this Church, fully to recognize, and deeply to feel, therefore, the weight of responsibility which the Baptismal Covenant lays upon them and their children. It is still true, that, if the Baptism of Infants be not recognized as requiring such godly training as may secure, by the Divine blessing, the submission of their whole nature, body, soul, and spirit, to the renewing and sanctifying influences of the Holy Ghost, then the mind of Christ, and the purpose of the Church, for the child, are not fulfilled. If, refraining henceforth, from discussions of words, in the acceptation of which there seems to be far less of real disagreement than has been imagined, we might, now, give ourselves, with one heart, to the rearing of our children in the fear of GOD, and to securing the great work of their salvation. Then we shall have succeeded in rendering our formularies so practical, and so fruitful in godliness, as to elevate the whole sentiment of the Church to a lofty spirituality, not likely to be disturbed, by agitations, to which, perhaps, we have subjected ourselves by manifold inconsistencies between our professions and our practices, in the relations we bear to GOD in covenant. Of course these sorts of proclamations depends on Episcopalians actually having concerns about biblical theology and not just a mild concern for sounding interested in social justice.
What happened to this group? Why do we know next to nothing about the Evangelical Episcopalians (unless we embark on scholarly research…)? The answers to these questions are mostly historical conjecture but some observations can be made. It is somewhat unorthodox to present the conclusion before the body of a text but I intend to do so right now. In the decades following the Civil War and the close of the 19th century, the Evangelical party began to divide amongst itself, due to a number of issues, some theological and some political. A number of Evangelicals became convinced that "Evangelical" and "Episcopalian" were incompatible. These left the PEC, under Bishop Cummins, and formed the Reformed Episcopal Church in 1873. Around this same time a number of the leaders of the Episcopal Church passed on, such as Charles Pettit McIlvaine (1799-1873), Manton Eastburn (1801-1872), Benjamin Bosworth Smith (1884), etc. These giants held to the traditional Protestantism of Anglicanism but failed to pass on the doctrine of the Church to the following generation. The next generation latched on to the spirit of Evangelicalism but not the teaching. In this sense, they preserved the notions of experience and liberality (see Butler's book) but did not uphold the teachings that made these experiences viable. For example, Phillips Brooks is an example of this second generation that liberalized. The form of Evangelical religion remained in the Episcopal Church until the advent of the 1979 Prayer Book, that being a generally anti-Ritualistic ceremonial, with Morning Prayer as the principal service, however, the problem was that by 1900 the theological rationale for this form was lacking and led to the current state of affairs.
What was the picture like before this? I intend to provide a broad overview of the picture before the turn of the 20th century.
Markedly different, actually. The story of Evangelicalism in the Colonial Church is one of rejection. The common worldview of the Colonial Church was the Restoration moralism, coupled with the rationalism of the age. George Whitefield's tours of the American Colonies showed that most of the Anglican clergy were not receptive to his message or methods (although some did receive him, the general response was negative). A personal theory of mine is that the negative reaction from the Anglican clergy towards George Whitefield (and other evangelists) is one of the reasons why evangelicalism in the US has not gravitated towards the "established" church, as it has in the United Kingdom (granted, other factors played a role in that development). Although the majority of Anglican clergy rejected the robust Protestantism of Whitefield, many did not. For example, Devereux Jarrat, rector of Bath parish in Dinwiddie County, was one such presbyter who embraced Whitefield's evangelicalism and became one of the early leaders of the Evangelical movement in the Colonial Church and early PEC. He was converted by evangelical Presbyterians but remained attached to the Church of England throughout his life. Similarly to McIlvaine in the 19th century, Jarrat decided to remain in the Church of England and promote Evangelical religion therein. Jarrat died in 1801, seeing much of his work in the 1770's destroyed by the American Revolution. However, others were ready to pick up the torch. For example, Joseph Pilmore, a Methodist missionary to the Colonies later returned to be ordained in the PEC in 1785, rector of various churches in Pennsylvania, Pilmore carried on the Evangelical witness until his death in 1825.
At this point the transition from the Colonies to Episcopal Church occurs. One of the struggles of the early PEC was the consecration of bishops. The first consecrated was Samuel Seabury, a High Churchman. Other early bishops were William White and Samuel Provoost, both rationalists. The early bishops of the Church were pessimistic about its future and had to deal with very difficult decisions of how to continue as Anglicans in the new Republic. The second generation of Episcopal bishops, however, was a far more energetic and visionary group than the original bishops. In 1811, John Henry Hobart, the High Church bishop of New York was consecrated, who grew the Church in New York State through his personal ministry. Additionally, Alexander Viets Griswold, an Evangelical, was consecrated bishop of the Eastern Diocese (New England) and grew the Church there. Richard Channing Moore, another Evangelical, was consecrated the second bishop of Virginia in the same year. This second generation of bishops provided the needed leadership for the Episcopal Church to grow and develop as its own entity. The next generation of bishops consecrated also includes a number of prominent Evangelical leaders. William Meade was consecrated third bishop of Virginia in 1829, who would later be a leader in the fight against Tractarianism. Benjamin Bosworth Smith was consecrated as the first bishop of Kentucky in 1832. The greatest leader of the Evangelical party, Charles Pettit McIlvaine, was consecrated as second bishop of Ohio in 1832 (and would lead the party until his death in 1873). Other notable Evangelical bishops include, Leonidas Polk (1838) and Manton Eastburn (1842), who would also help lead the campaign against Tractarianism.
The story of the Evangelical party is one of tremendous success, followed by disunity and collapse. Throughout the 19th century, largely by the leadership of McIlvaine, the Evangelical party established itself as an Episcopal movement, grew in numbers, and left its legacy. It established two theological colleges: Virginia Theological Seminary and Kenyon College. It established several of its own societies such as the Protestant Episcopal Society for the Promotion of Evangelical Knowledge and participated in other inter-denomination societies such as the Evangelical Alliance and the American Bible Society. They also published a number of books, tracts, sermons, and other literature, as well as operating various newspapers to promote their viewpoint.
The distinctiveness of Evangelical Episcopalians lay in their maintaining of the theology of the Anglican formularies and the worship of the Church, whilst adapting to the culture of the time. Central to their vision was the conversion experience or the mature decision to follow Jesus Christ. The sinfulness of man was central to the Evangelical worldview as it is in classical Protestantism. The Evangelical Episcopalians were predestinarian in outlook, yet managed not to get tied down in the Calvinist-Arminian debates, espousing a form of single predestination. The practice of Evangelical religion came through the liturgy of the Church, which they maintained was thoroughly Protestant and Reformed and which promoted Evangelical religion. The Evangelicals insisted that liturgical form was meaningless without a converted heart. In addition to the public liturgy of the Church, the Evangelicals used prayer meetings, preaching, Bible classes, and revivals as means of promoting "true religion" or the conversion of souls. The prayer meeting was the most notable mark of an Evangelical parish, marked by a simplified liturgy, lectures and sermons, hymn-singing, Scripture reading, and extemporaneous prayer, it was also the thing that caused the most strife between Evangelicals and High Churchmen. They also adapted the revival to the Episcopal liturgy by incorporated revivalistic services to the liturgy of the Book of Common Prayer. Evangelical Episcopalians approached confirmation from a classical Protestant point of view, whilst injecting it with evangelical fervor. They regarded the confirmation rite as the time for adults to show their conversion and trust in Jesus Christ as Savior. Evangelical Episcopalians were in close contact with other Protestants and tended to follow the trends of those churches. For instance, during the 19th century premillennialism became a common belief among American Protestants, especially the dispensationalist variety. This was also popular among Evangelical Episcopalians.
Overall, the Evangelical Episcopalians provided a means of being both an Anglican and an Evangelical in the Protestant Episcopal Church. They took the theology of the Church seriously and tried to infuse its forms with heart religion. One can argue about their successes and failures but it is more important to acknowledge their existence and to allow for that tradition to continue to flourish in the Church today.