The overall ratings of 15 oil and gas stocks are down on Portfolio Grader this week. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Crescent Point Energy Corp. (CPG) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). In Portfolio Grader’s specific subcategories of Earnings Revisions, Earnings Surprise, Cash Flow and Margin Growth, CPG also gets F’s. The trailing PE Ratio for the stock is 98.40. For a full analysis of CPG stock, visit Portfolio Grader.

Golar LNG Partners’ (GMLP) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Golar LNG Partners owns floating storage and regasification units and liquefied natural gas carriers. To get an in-depth look at GMLP, get Portfolio Grader’s complete analysis of GMLP stock.

Kinder Morgan, Inc. Class P (KMI) is having a tough week. The company’s rating falls from a D to an F. Kinder Morgan is a pipeline transportation and energy storage company. The stock has a trailing PE Ratio of 28.30. For more information, get Portfolio Grader’s complete analysis of KMI stock.

Slipping from a D to an F rating, Cosan Limited Class A (CZZ) takes a hit this week. Cosan is a fully integrated company in the renewable energy and infrastructure segments in Brazil. The stock gets F’s in Cash Flow and Margin Growth. The trailing PE Ratio for the stock is 35.50. To get an in-depth look at CZZ, get Portfolio Grader’s complete analysis of CZZ stock.

The rating of Goodrich Petroleum Corporation (GDP) slips from a C to a D. Goodrich Petroleum explores, develops, produces and acquires oil and natural gas properties. The stock gets F’s in Earnings Growth, Earnings Revisions, Equity and Cash Flow. As of April 4, 2014, 29.3% of outstanding Goodrich Petroleum Corporation shares were held short. For a full analysis of GDP stock, visit Portfolio Grader.

This week, EXCO Resources, Inc.’s (XCO) rating worsens to an F from the company’s D rating a week ago. EXCO Resources is an oil and natural gas company involved in the exploration, exploitation, development and production of onshore North American oil and natural gas properties. The stock gets F’s in Earnings Surprise, Equity and Cash Flow. As of April 4, 2014, 15.8% of outstanding EXCO Resources, Inc. shares were held short. The stock currently has a trailing PE Ratio of 53.30. For more information, get Portfolio Grader’s complete analysis of XCO stock.

Calumet Specialty Products Partners, L.P. (CLMT) earns an F this week, falling from last week’s grade of D. Calumet Specialty Products produces hydrocarbon products in North America. The stock gets F’s in Earnings Growth, Earnings Momentum and Earnings Revisions. Cash Flow and Margin Growth also get F’s. To get an in-depth look at CLMT, get Portfolio Grader’s complete analysis of CLMT stock.

Chevron Corporation (CVX) earns an F this week, moving down from last week’s grade of D. Chevron is an integrated energy company with operations in countries located around the world. For a full analysis of CVX stock, visit Portfolio Grader.

Plains All American Pipeline, L.P. (PAA) gets weaker ratings this week as last week’s C drops to a D. Plains All American Pipeline is involved in interstate and intrastate crude oil pipeline transportation and crude oil terminalling storage activities. For more information, get Portfolio Grader’s complete analysis of PAA stock.

This week, TransCanada Corporation (TRP) drops from a D to an F rating. TransCanada develops and operates energy infrastructures, including natural gas pipelines. The stock’s trailing PE Ratio is 27.30. To get an in-depth look at TRP, get Portfolio Grader’s complete analysis of TRP stock.

Enbridge (ENB) experiences a ratings drop this week, going from last week’s D to an F. Enbridge is in the business of transportation and distribution of crude oil and natural gas primarily in Canada and the United States. The stock gets F’s in Earnings Growth, Earnings Momentum and Cash Flow. The trailing PE Ratio for the stock is 81.50. For a full analysis of ENB stock, visit Portfolio Grader.

This week, StealthGas (GASS) drops from a C to a D rating. StealthGas offers marine transport services for liquefied petroleum gas producers and users. The stock receives F’s in Earnings Growth, Earnings Revisions, Earnings Surprise and Cash Flow. For more information, get Portfolio Grader’s complete analysis of GASS stock.

This is a rough week for Ultrapar Participacoes S.A. Sponsored ADR (UGP). The company’s rating falls to F from the previous week’s D. Ultrapar is engaged in the fuel distribution and chemical businesses in Brazil. For a full analysis of UGP stock, visit Portfolio Grader.

Gevo (GEVO) earns an F this week, falling from last week’s grade of D. Gevo operates as a technology development company for biobutanol. The stock gets F’s in Equity, Cash Flow and Sales Growth. For more information, get Portfolio Grader’s complete analysis of GEVO stock.

The rating of PDC Energy (PETD) slips from a C to a D. PDC Energy is an oil and gas company with drilling and production operations in the Rocky Mountains, the Appalachian Basin and Michigan. The stock gets F’s in Earnings Revisions and Cash Flow. As of April 4, 2014, 11.3% of outstanding PDC Energy shares were held short. To get an in-depth look at PETD, get Portfolio Grader’s complete analysis of PETD stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.