This week, the ratings of 17 oil and gas stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Crescent Point Energy Corp. (CPG) ratings are on the decline this week as the company earns an F (“strong sell”). Last week, it received a D (“sell”). In Portfolio Grader’s specific subcategories of Earnings Revisions, Earnings Surprise, Cash Flow and Margin Growth, CPG also gets F’s. The stock has a trailing PE Ratio of 43.50. To get an in-depth look at CPG, get Portfolio Grader’s complete analysis of CPG stock.

This week, Golar LNG Partners (GMLP) falls to a D (“sell”), worse than last week’s grade of C (“hold”). Golar LNG Partners owns floating storage and regasification units and liquefied natural gas carriers. For more information, get Portfolio Grader’s complete analysis of GMLP stock.

Cosan Limited Class A’s (CZZ) rating weakens this week, dropping to an F versus last week’s D. 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. Shares of the stock have been exchanging at an usually rapid pace, twice the rate of the week prior. To get an in-depth look at CZZ, get Portfolio Grader’s complete analysis of CZZ stock.

The rating of Goodrich Petroleum Corporation (GDP) declines this week from a C to a D. Goodrich Petroleum explores, develops, produces and acquires oil and natural gas properties. In Earnings Growth, Earnings Revisions, Equity and Cash Flow the stock gets F’s. As of Dec. 19, 2014, 37.6% of outstanding Goodrich Petroleum Corporation shares were held short. For more information, get Portfolio Grader’s complete analysis of GDP stock.

Slipping from a D to an F rating, EXCO Resources, Inc. (XCO) takes a hit this week. 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 Dec. 19, 2014, 12.3% of outstanding EXCO Resources, Inc. shares were held short. To get an in-depth look at XCO, get Portfolio Grader’s complete analysis of XCO stock.

Calumet Specialty Products Partners, L.P. (CLMT) gets weaker ratings this week as last week’s D drops to an F. Calumet Specialty Products produces hydrocarbon products in North America. The stock receives F’s in Earnings Growth, Earnings Momentum and Earnings Revisions. Cash Flow and Margin Growth also get F’s. For more information, get Portfolio Grader’s complete analysis of CLMT stock.

Plains All American Pipeline, L.P. (PAA) is having a tough week. The company’s rating falls from a C to a D. Plains All American Pipeline is involved in interstate and intrastate crude oil pipeline transportation and crude oil terminalling storage activities. To get an in-depth look at PAA, get Portfolio Grader’s complete analysis of PAA stock.

This is a rough week for TransCanada Corporation (TRP). The company’s rating falls to F from the previous week’s D. TransCanada develops and operates energy infrastructures, including natural gas pipelines. For more information, get Portfolio Grader’s complete analysis of TRP stock.

Enbridge (ENB) earns an F this week, falling from last week’s grade of D. 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 stock currently has a trailing PE Ratio of 58.20. To get an in-depth look at ENB, get Portfolio Grader’s complete analysis of ENB stock.

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 gets F’s in Earnings Growth, Earnings Revisions, Earnings Surprise and Cash Flow. For more information, get Portfolio Grader’s complete analysis of GASS stock.

Midcoast Energy Partners LP Class A (MEP) experiences a ratings drop this week, going from last week’s C to a D. The stock gets F’s in Earnings Revisions and Cash Flow. The trailing PE Ratio for the stock is 194.60. To get an in-depth look at MEP, get Portfolio Grader’s complete analysis of MEP stock.

The rating of Ultrapar Participacoes S.A. Sponsored ADR (UGP) slips from a D to an F. Ultrapar Participacoes is engaged in the fuel distribution and chemical businesses in Brazil. For more information, get Portfolio Grader’s complete analysis of UGP stock.

This week, Gevo’s (GEVO) rating worsens to an F from the company’s D rating a week ago. Gevo operates as a technology development company for biobutanol. The stock gets F’s in Equity, Cash Flow and Sales Growth. To get an in-depth look at GEVO, get Portfolio Grader’s complete analysis of GEVO stock.

PDC Energy (PETD) earns a D this week, moving down from last week’s grade of C. 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. For more information, get Portfolio Grader’s complete analysis of PETD stock.

Chevron Corporation (CVX) experiences a ratings drop this week, going from last week’s D to an F. Chevron is an integrated energy company with operations in countries located around the world. To get an in-depth look at CVX, get Portfolio Grader’s complete analysis of CVX 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’s trailing PE Ratio is 33.20. For more information, get Portfolio Grader’s complete analysis of KMI stock.

Slipping from a C to a D rating, Plains GP Holdings LP Class A (PAGP) takes a hit this week. The stock gets F’s in Earnings Momentum and Cash Flow. The stock currently has a trailing PE Ratio of 70.80. To get an in-depth look at PAGP, get Portfolio Grader’s complete analysis of PAGP 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.